Winston Peters has been NZ First's only leader since the party was formed. Tabuteau is its fifth deputy.

The first was Tau Henare, elected as the party's second MP in 1993, from the Northern Maori electorate. The second was Peter Brown, from 1998 to 2009, when the party had been tipped out of office. Tracey Martin filled the vacancy after the party was returned to Parliament in 2011.

Last term Ron Mark organised a coup against Martin when he returned to national politics in 2014 after a six-year hiatus, and amid speculation that former Labour MP Shane Jones was planning to join New Zealand First and could be a potential successor.

Now Tabuteau has ousted Mark, the party's longest-serving MP after Peters.

Ironically for one of Parliament's most combative players, Peters avoids situations of conflict around him. It is understood he was happy with Tracey Martin as deputy last term and was not impressed by Ron Mark rolling her, but did nothing to stop it. He certainly did nothing to stop Tabuteau rolling Mark.

Tabuteau's rise through the party has been more tortoise than hare.

Now 43, he was only 18 when he piled into the family car with his parents and drove from Rotorua to Auckland for the launch of the party by Peters in July 1993. He was pretty much hooked right then.

Tabuteau's mother was the sister of Tom Gear, one of Peters' oldest and closest Tauranga friends, and his parents were very political, he says.

"If you remember back at that time, Winston was such a dynamic force and just drew people in. Mum and Dad were definitely part of that, that's for sure."

When the party was launched, Tabuteau was a student at Rotorua's Waiariki Polytechnic, studying business: he later became head of its business school. He was born and educated in Rotorua and returned home after getting a business degree at Waikato.

On his mother's side, he affiliates to the Ngati Ngararanui, Ngati Rangiwewehi, and Ngati Whakaue tribes of Rotorua and through Tauranga Moana to Ngai Te Rangi and Ngati Tapu.

On his father's side, he affiliates to La Rochelle, France (back to 1601), and to Murupara where his father and his father's brother ran Tabuteau's Drapery for many years.

He gave a moving tribute in his maiden speech in 2014 about how proud his parents, Maria and David, and sister Stacey would all be if they had lived to see him in Parliament - cancer and heart conditions claimed all of his immediate family.

Tabuteau has done the hard yards in the party, serving as a member of the local Rotorua branch committee, then treasurer, then chairman, then as a candidate, unsuccessfully, in 2002, 2005 and 2011 (because he was ranked too low for the number of list MPs elected), then successfully in 2014 and again in 2017 when he was ranked No 4.

He promoted a private member's bill from the backbench last term which would ban New Zealand signing up to any trade deal with an investor-state dispute settlement provision (essentially private arbitration), which is now Government policy.

"Thank you for noticing that ," he says.

After the decision that NZ First would form a coalition government with Labour, Tabuteau was made an under-secretary to Peters in Foreign Affairs and to Shane Jones in Regional Development.

So does Tabuteau want to eventually take over from Peters, who has led New Zealand First by force of personality since he launched it in 1993?

"It's a good question," says Tabuteau "because I need to tell people that, honestly, I haven't even thought about it.

"This is about supporting the leader, it's about working with the caucus and I've got at least two or three years to prove myself to my caucus colleagues and the New Zealand public and differentiate ourselves, talk about NZ First as a coalition partner so people can see what we do bring to this coalition Government."

Because Tabuteau is not overtly ambitious, his elevation is more likely to reduce attention on the succession than would have been the case if, say, Shane Jones had sought the job or Tracey Martin had tried to get it back.

Jones is still considered a prospective candidate after Peters goes, but having been a party member for less than a year, he has time to prove himself a worthy contender, assuming Peters is in no hurry to call time on politics.

NZ First has fallen below 5 per cent in the two polls taken since the election: 3.8 per cent in the Newshub Reid Research poll in late January and 3 per cent in the 1 News Colmar Brunton poll in mid February.

Auckland University Emeritus Professor of Politics Raymond Miller says there are several reasons Peters would not be looking to retire any time soon - including those poll results.

"First, at present his workload is manageable. He is obviously able to cope with his present responsibilities. There are a lot of people around his age and over who still maintain a fairly busy life.

"Secondly, he does enjoy the esteem associated with being Minister of Foreign Affairs and Deputy Prime Minister and, of course, the prospect of becoming Acting Prime Minister. These seem to suit his ambitions, and he has had previous experience in those positions."

"Thirdly, as the personification of the party and its proven campaigner, I do feel he needs to be around in 2020 because as we know, small parties that go into Government tend to be punished by voters and he is the sort of person who will be able to lift it up over 5 per cent again, possibly. "

It would be a hard ask but Peters has the experience to do that, he says.

"I'm not convinced Fletcher would have that ability. Shane Jones is the probable one."

However he would not rule out Mark or Martin entirely.

Meanwhile, he says Tabuteau is a safe pair of hands "and he is able to delay any rivalry from any other member of the caucus over the next couple of years at least".

Staying in Government is a big motivating factor to fight another election, says Miller, particularly for a minor party leader who has been sitting waiting so long.

"When the cards do fall in their favour, they take the opportunity with both hands, basically because it's unlikely to come again."

National's Todd McClay is unequivocal on NZ First's future.

"My view is that when Winston Peters goes, NZ First is finished. The question is who in their caucus has the most profile to lead the party after Winston Peters and it is not clear anybody does."

He says Jones has a higher profile than the others but doesn't have the pedigree of the party.

"Whether Fletcher is the future or is merely keeping the seat warm I think is a whole other question to answer."

It has been a punishing schedule but, he says, Peters has been fine with the pace.

Tabuteau dismisses persistent rumours about Peters being in ill-health, which media outlets have received on a regular basis for a long time, alleging all manner of conditions, and all rejected by Peters.

"I have had exactly the same thing," says Tabuteau." I've been engaging a lot with business leaders and business owners of late in particular and they are all asking the same thing. Some of them are malicious and some are genuinely concerned.

"But I have been able to honestly tell them 'look, I just think they are horrible rumours, started by who knows'. He is in fighting-fit health, he really is. He is doing a fantastic job if I can humbly say so."

The Pacific Mission had provided amazing engagement, he said.

"It has been wonderful actually. And Winston is fine. Winston is doing very well."

Tabuteau's delegation under Foreign Affairs specifically cites New Zealand relations with the Pacific, and non-traditional partners in Latin America, the Middle East and Africa.

His delegation under Regional Development include initiatives under the Maori economic development strategy and tourism projects.

The mission arrived back in New Zealand yesterday and it is back to the business of Government and the business of raising the party's identity within that Government.

"We have to be very deliberate about celebrating the NZ First success within the Government," Tabuteau says.

"It is just wonderful that we have this amazing Prime Minister who is doing a fantastic job and people can see that.

"But from NZ First, we have to make sure that the New Zealand public understand we are a big part of that.

"That is the driver of a political organisation. It is about public support and public understanding."