A Wellington man has publicly thanked Metlink and NZ Police for not forcing him and his wife to wear a mask while riding the train in Wellington, despite level 2 rules requiring masks on public transport.

Joachim Wanihi's Facebook post, featuring a photo of himself and his wife unmasked on the train, has gone viral, with more than 3000 comments, creating lively discussion about whether or not they should be wearing a mask.

"Appreciate the Metlink staff & NZ Police for their professional conduct in approaching us for not wearing masks on the train this morning," Wanihi wrote.

"The train guard asked if we knew it was mandatory to wear a mask? We said that we are aware the government website said we cannot be stopped from entering the train without wearing a mask. He was gracious and took our tickets."

According to the man, the police then got on the train and asked the couple whether they would like a mask.

"We thanked him but said no thank you. He smiled and said have a nice day," he said.

"Know your rights, but don't be an a**hole. My wife pictured here basking in God's grace."

Wanihi did not respond to a request for further comment.

In the comments, many slammed the couple's "selfish" behaviour and said they were not acting as part of the "team of 5 million".

"Don't be asking for medical help if you get Covid - get on your knees n pray to your God," one person commented.

"It's a sign of respect, especially since a lot of our elderly people ride public transport," another Facebook user pointed out.

It is not clear why the couple chose to travel without a mask despite it being mandatory.

In a separate post, the man says that he understands police will eventually "begin to enforce this mandate" and adds that that's when he'll "need to make alternative arrangements" for his wife to go to work.

Under the new alert level 2 rules, which the whole country is currently under, masks are required on all public transport across New Zealand, including buses, trains, ferries and even taxis and Ubers.

New Zealand Police would not comment on this specific case but say that, since the new rules began at 11.59pm on Sunday, they are using "an education and encouragement approach".

With face-covering now mandatory on public transport, police say they are distributing thousands of face masks to members of the public, as part of their approach.

"We recognise this requirement is something new for many Kiwis and it's something people may not have been used to doing previously," Assistant Commissioner Richard Chambers said in a press release.

"While these masks have been designed to be disposable, as part of our education approach it is hoped that it makes the idea of wearing a face covering become more familiar for the public.

"Our response to Covid-19 has been to work with the public first and remind them of what is required from them."

Police say the overwhelming majority of people have been using masks on public transport.

"The feedback I have received from staff has been that interactions with the public today have been positive and that people were aware of the importance of wearing a face mask," Chambers said in a statement on Monday evening.

"We are pleasantly surprised at the level of high compliance and New Zealanders should be congratulated for this," he said.

"For those people who are struggling with why masks are mandatory, I would encourage you to reflect on the damage this pandemic has done overseas. We are in a good position in New Zealand and it's important to we continue to do the right thing."

Metlink has been approached for comment.