UPDATED 6.16PM The Prime Minister is sticking to his decision not to release his tax returns, saying his opponents are trying to have it both ways when it comes to his finances.

Labour Leader Andrew Little decided to release his tax records this afternoon in the wake of the Panama Paper allegations, and has challenged John Key to do the same.

SEE ALSO: Key accused of not taking tax avoidance seriously

Mr Key said yesterday that his tax affairs were above board and that he had never put assets into a foreign trust.

"I've never used a foreign trust, no, I've never used a foreign trust. I've only had two trusts," he said.

But Mr Little now wants him to prove this claim. The Labour leader said it would be "unsurprising" if Mr Key had sought to minimise tax on his assets because of his financial background.

"He is our Prime Minister now. And he is dealing with an issue about tax and the morality of tax dodging. And I think ... to give New Zealanders an assurance that he is squeaky clean and above board he should be disclosing his tax records in just the same way that David Cameron has now agreed he is going to disclose his."

Mr Little said he had gathered his tax records back to 2010, and tabled them this afternoon in Parliament.

The records covered Mr Little's time as chief executive of the EPMU, where his income rose to $178,000, and his first three years in Parliament.

After tabling the documents, Labour MPs yelled across the House: "Show us yours, John."

But the Prime Minister is dismissing Mr Little's move.

"It's a stunt. He's on seven percent, he's desperate," Mr Key said.

The Prime Minister is ruling out releasing his own tax records, saying to do so you'd have to see the tax return for his blind trust and he doesn't even know what's in it.

Mr Key said people "can't have it both ways" - make sure he doesn't know his investments, but on the other hand somehow dig in a tax return that might show his blind trust's details.

The Prime Minister shot back in Parliament this afternoon, saying that Mr Little should be tabling his CV instead, "because he will be out looking for another job soon" - a reference to Mr Little and Labour's poor poll results.

The register of pecuniary interests, published today, confirmed that all of Mr Key's investments remained in the blind trust, the Aldgate Trust. He was also a beneficiary of the Key family trust.

The register also revealed, however, that the Prime Minister has a short term deposit with a firm called Antipodes Trust Group Limited, a trustee company which specialises in foreign trusts and provides legal services for Mr Key.

According to the company's own website it is a specialist provider of trustee and associated services for foreign trusts and uses New Zealand as it jurisdiction of choice.

However there is nothing specific in Mr Key's declaration that suggests he uses a foreign trust.

Mr Key's office said the Prime Minister's relationship is with the company's executive director, Ken Whitney, rather than with the company itself.

A spokesperson said Mr Whitney has been the Prime Minister's lawyer for a long period of time and the difference between this year's declaration and last year's is that Mr Whitney has changed firms.

The PM's office said the short term deposit is used to pay for any costs incurred from the Prime Minister's family trusts.