Tucked away in a seaside bar in Nelson, Phil Goff releases just a little bit of mongrel.

He's speaking to a crowd of Labour supporters at the end of his caucus meeting in the city and one has just asked the question that has been taxing his own mind since the day National won the election - what to do about that "nice Mr Key" image the public has.

"Ah yes," Mr Goff says, laughing. "Smile and Wave!"

It is a reference to the moniker given to the Prime Minister by the Labour-affiliated Standard blog to reflect its view that John Key dismisses problems with a smile rather than considering them with the gravitas required.

Conveniently, that nice Mr Key has handed Labour some grist that very day by claiming Maori co-leader Tariana Turia was not upset about his last-minute decision not to include Te Urewera National Park in a settlement with Tuhoe.

As it turned out, Mrs Turia was indeed upset and film of her marching up to the camera lens to tell the nation of Mr Key's mistake had screened only half an hour earlier.

"I saw 'Smile and Wave' on telly tonight," Mr Goff tells his audience.

"That was a classic example of how the National Party is telling Maori one thing and the rest of the country another thing. When you speak out of both sides of your mouth it will catch up on you."

He tells them Mr Key is king of the photo opportunity, "slick" and "one of the best I've seen," going as far away as Afghanistan to snatch publicity.

But he says people make up their minds on realities, not photos.

It's a break from his usual practice of refraining from attacking Mr Key's personal style, wary of how such criticism of a popular PM might look.

But Labour has been trying to paint Mr Key's apparent unflappability about the chaos that occasionally erupts as a character flaw for some time. While the Maori Party may be reeling from what it sees as a betrayal by Mr Key, Labour is delighted and more than ready to crow that the Emperor has no clothes.

Mr Goff is more relaxed than normal - this is not a scripted meeting, he knows the audience is friendly and it's a casual occasion.

He fields questions about mining on conservation land, cuts to adult education, and changes to ACC, telling his listeners such changes will all be reversed should Labour regain the Treasury benches, and in fact "we are going to be doing a lot of reversing".

This is the hard graft of Opposition work, travelling around the country and meeting people.

Sometimes, if they're lucky, one of those people will tell them something they can try to bludgeon the Government with in Parliament - a funding cut that has had a bad effect on someone, a policy that has ruined a life.

There's also a requirement to show some humility. So when one supporter anguishes over how long it will take for an apparently deluded nation to see the error of its ways and reinstate Labour, Mr Goff answers with a simple statement: "We are not entitled to expect people's votes, we've got to go out there and earn them."

He gets a warm response. But at one point, one of the audience in Nelson notes Mr Goff is speaking at that meeting only to the converted.

All are aware the polls would indicate that that nice Mr Key has quite a few more converts.