Sydney radio host Alan Jones has been told his contract will be terminated if he again makes attacks similar to his comments about NZ Prime Minister Jacinda Ardern.

Jones issued an apology for his repeated attacks on Ardern after a major advertiser pulled support for his radio programme.

Macquarie Media chairman Russell Tate said Jones had been advised he would be fired if a similar incident occurs.

"Notwithstanding his apologies, I have today discussed the matter with Alan and advised him that any recurrence of commentary of this nature will result in the termination of his contract," he said in a statement.

After saying Prime Minister Scott Morrison should "shove a sock down her throat" and claiming the New Zealand Prime Minister "has no idea what she's talking about," Jones made an unexpected appearance on 2GB on Friday evening to offer his regret.

"I was wrong, and I apologise," he told listeners.

"When these things happen, you've just got to man up, pivot, face it and apologise for it.

Alan Jones in 2018. Photo / Getty

"We don't want that sort of offence to be given in 2019. I accept it's careless. I accept it's wrong."

• Alan Jones tells Ardern to 'shut up', stop hugging people

"She's both a politician and a mother," he continued.

"I am certainly wanting the very best for her family and I hope at some stage we are able to talk.

"In this game, you've got to choose your words carefully and I didn't do that. I have erred and made a mistake. I was wrong. Now when you do that, you've got to be man enough to simply say I was wrong, I apologise.''

In his heated attacks Jones accused Ardern of "duplicitously" excluding the agriculture sector from New Zealand's pledge to become carbon neutral by 2050.

"Someone's got to tell this woman to keep quiet, put a sock in it.

"It's a metaphorical way of saying 'shut up'. I wish she would shut up. I don't know how New Zealanders handle this."

He also spoke to Newstalk ZB.

"It's easy to run around the world, smile at people and look good and hug people and all the rest of it," Jones told ZB's Mike Hosking.

"At home, people vote for a particular reason. They want things to be done. And in your country and our country, they're not being done."

Jones was slammed after also labelling Ardern a "complete clown" and urging Australian Prime Minister Scott Morrison to "shove a sock down her throat".

He was responding to Ardern's assertion that Australia would have to "answer to" other Pacific nations unless it stepped up its efforts to combat climate change.

"Here she is preaching on global warming and saying that we've got to do something about climate change," Jones said.

"The fact is New Zealand's carbon dioxide has grown by 10.8 per cent per capita since 1990. Ours has grown by 1.8 per cent.

"I just wonder whether Scott Morrison is going to be fully briefed to shove a sock down her throat.

"She is a joke, this woman, an absolute and utter lightweight.

"These people are an absolute joke and Jacinda Ardern is the biggest joke."

Morrison briefly addressed Jones' comments after emerging from a 12-hour meeting with other Pacific leaders on Thursday afternoon, saying he was "disappointed" and they were "way out of line".

"The comment has been relayed to me; on what's been reported to me, I find that very disappointing and of course that's way out of line," the Prime Minister said.

"I have two daughters, so you can expect that's how I would feel personally about it. I'll leave others to explain what they've said and how they've said it."

Morrison's predecessor Malcolm Turnbull said Jones should apologise for "his misogynistic rant".

Ardern herself declined to comment.

"I don't think I will give that comment the light of day. I think I'll just leave it where it is," she told reporters in Tuvalu.

Prime Minister Jacinda Ardern and Fijian Prime Minister Frank Bainimarama. Photo / Jason Walls

In a statement, Jones initially claimed he had been "wilfully misinterpreted".

"Of course what I meant to say was that Scott Morrison should tell Ms Ardern to 'put a sock in it'," he said.

"There are many people who would relish the opportunity to misinterpret things that I have said as we have seen online this afternoon. Of course I would not wish any harm to Jacinda Ardern.

"This wilful misinterpretation distracts from my point that she was wrong about climate change and wrong about Australia's contribution to carbon dioxide levels."

Morrison's appearance at the Pacific Islands Forum this week came amid pressure from Pacific leaders for Australia to take greater action on climate change.

Ardern's comment that Australia would "answer to" other countries added to that pressure.

"We will continue to say that New Zealand will do its bit. And we have an expectation that everyone else will as well. We have to. Every single little bit matters," Ardern said after disembarking her plane in Tuvalu's capital, Funafuti, where she encountered a group of local children singing: "Save Tuvalu, save the world."

"That is why New Zealand has joined that international call. That is why we speak, I believe, strongly on the international stage around these issues. But ultimately we have to take responsibility for ourselves," she continued.

"Australia has to answer to the Pacific. That is a matter for them."

The Australian's environment editor Graham Lloyd was more restrained than Jones, but also criticised Ardern.

"Demanding Australia abandon its coal production and exports for the good of the climate in the Pacific is akin to asking New Zealand to give up its love affair with sheep," Lloyd wrote.

"Ardern is naive if she believes such moves would be economically feasible or in the best interests of regional stability."

The Daily Telegraph's Tim Blair, meanwhile, made the point a bit more facetiously.

"New Zealand's 'little but' of carbon dioxide output doesn't make the slightest bit of difference to the fate of Pacific Islands or anything else. Does Wellington even have factories?" he wrote.

Meanwhile, in Tuvalu, Fijian Prime Minister Frank Bainimarama sent a message of his own backing up Ardern.

"When combatting climate change, it's good to have an ally like New Zealand in your corner. Together, we can save Tuvalu, the Pacific, and the world. Vinaka vakalevu for the passion you bring to this fight, @jacindaardern," he wrote on Twitter.

NZ's Deputy Prime Minister Winston Peters, who is also Foreign Minister, then walked back her comments and even defended Australia during an interview on ABC radio.

"Let's make no bones about it, Australia has been a great neighbour in the Pacific. They've put a lot of effort and a lot of care and a lot of attention and a lot of sound foreign policy over decades in the Pacific. Before people rush to judgment they should remember that," Peters said.

He said every nation at the Pacific forum needed to outline its response to the challenge of climate change.

Deputy Prime Minister Winston Peters. Photo / File

"The Australians have provided their response. The rest of us have provided ours. And to my knowledge it's not been the New Zealand Prime Minister who's raised the questions about the Australian response, it's been other members at the forum. But not our Prime Minister," he said.

Australia's response has been to redirect A$500 million from its foreign aid budget to help the Pacific nations mitigate the effects of climate change.

But that has not been enough to satisfy all the other leaders.

Tuvalu Prime Minister Enele Sopoaga said the situation was "dire" for his country, whose highest point is just four metres above sea level, and the A$500 million funding package would not make him "shut up" about climate change.

Peters suggested criticism of Australia did not take in the full picture, and China needed to be brought into the conversation as well.

"You need to look at everybody, not just Australia, but also who is getting that coal and what things they are doing with it," New Zealand's Deputy Prime Minister said.

"What I'm sadly hearing is variations on a theme that (Pacific leaders are) all attacking the Australian Prime Minister, or that they've all taken the view, including New Zealand's Prime Minister, that the Australians are somehow acting incorrectly when that is not the proper picture or the real picture at all.

"There's a bit of a paradox here.

"There are many Pacific countries that are seeking cheap loans from China. Now those loans are on the backs of coal-fired everything in mainland China, as we well know. So you know, there's a big picture we've got to contemplate here, and we've got to ensure we act in this big picture, we act with consistency and integrity.

"You've got to look at everybody. Not just — for example, Australia's got coal and you're selling it. The next question is OK, who is getting that coal and what are they doing with it? We should keep our eyes on all the details."