A bit of anger over credit cards could earn Labour a bit of credit with voters, but there's a risk for a party that is still trying to prove its economic bona fides

Labour may just have stumbled on a wee goldmine. Former leader David Shearer has in recent days been taking some pot-shots at the banks. Not all out assaults, but he's been spraying bullets around at the 'big four' Australian-owned banks, complaining about their excessive profits and "rorting" of ordinary Kiwis.

It hasn't looked terribly coordinated, but it's an interesting tactic and reminiscent of Shane Jones and his attack in 2013 on the supermarket duopoly. What supermarkets and banks share in common is that we all need them, they make bucket loads of money in bad times and good, and they're owned largely by Australians.

They're an easy target. Boo! Hiss! Look behind you! And as the economy turns decidedly chilly this winter, people are looking for targets.

Shearer has raised the fact that the Australian-owned banks in New Zealand have a bigger profit margin than they do in Australia, which will grate. He also reckons farmers are starting to come under pressure from their banks, something the banks reject.

But the bullet most likely to hit the mark is his complaint about interest rates on credit cards. According to Shearer we Kiwis carry about $4 billion [corrected] of debt on our credit cards. And he asks a very telling question:

"Why is it that credit cards are still 17% and 18% when the banks’ lending has come from 8.5% right down to 3%? That margin has shrunk for the banks, but it hasn’t shrunk for the customers."

It's the sort of question a lot of New Zealanders won't have thought of, but when it's posed will go "yeah, why's that not come down?". In that way, it's like petrol prices and milk.

The banks say credit cards are covering unsecured loans, so the risk is high. They say most New Zealanders pay off their debt inside the interest-free period and don't pay a cent. That only 1-3% of New Zealanders pay only the minimum off their cards, which is much lower than most comparable countries.

But the banks made money eight years ago when their borrowing rates were around eight percent. So why do they need a bigger margin now? To that they seem to have no good answer. And it's one Labour can press for, and look like the champion of the little guy while they do it.

As with Jones' supermarket campaign, the party can latch onto existing disgruntlement (who loves their bank?) and show they care about things that hit people's pockets, not just the identity politics of yore.

It just has to be done with some tact, something that has not always been a Labour strong point. The risk is that Labour looks anti-business, anti-aspiration and wealth. That they don't appreciate the importance of a sound banking system, and so aren't yet the responsible economic managers voters need them to be.

Labour's performance has been patchy in recent months. Shrewdly, it acknowledges that no-one is really listening to it right now. Its strategy is to chip away at the government as much as it can while it strengthens internally and builds its competence for when people switch on again.

But Andrew Little's initial solidity has started to look a little dour. And the risk of doing so little now is that momentum is lost and people's preconceptions aren't challenged until it's too late. A few hiccoughs, like a bit of plagiarism here and some pretty tepid speeches there, raise fears amongst its supporters that the wobbly old Labour Party remains. But it's too early to tell. 

Perhaps the one thing being challenged is the sense that an Andrew Little Labour Party is a bit more confronting, a bit willing to work the centre and the populist line. The sense that it's closer to New Zealand First than the Greens these days tells you just how keen it seems to be to hug the middle. You can see that in its careful stance on the TPPA (riding the popular wave of scepticism without ever putting Phil Goff and the party's other free-traders in an impossible position) and its willingness to push ahead with its Chinese surname complaints, even in the face of anger from the left.

At the same time Little is working his way round big business and trying to show a friendly face to the corporate world, including the banks. Which makes you wonder whether Little's office signed off his releases on banks "rorting" New Zealanders.

Populism and drum-beating is always tricky when you're trying to look like you're ready to govern. Labour has to be careful to walk the tightrope between looking like responsible fiscal managers and using people's instinctive distrust of banks to win votes. But it's certainly an issue that could give it another bump in the right direction.