New links between the Prime Minister and a lobbying effort to protect foreign trusts has been labelled as a desperate smear.

LISTEN ABOVE: Green Party co-leader James Shaw speaks to Jack Tame about trust lobbying

Ken Whitney, the executive director of trust specialist Antipodes, wrote to then-Minister for Revenue Todd McClay on December 3, 2014, over concerns Inland Revenue were sizing up the sector.

LISTEN: PM must front on trust lobbying: Shaw

MORE: Frances Cook - PM's trust issues not a good look

REVEALED: PM's lawyer lobbied Govt not to change tax laws

New Zealand's trust regime recently made international headlines with the leak of the Panama Papers revealing the abuse of trust structures internationally by those seeking to launder money or avoiding tax.

But the Prime Minister insisted that it was very different from his end.

Key said people raised questions with him all the time, and he directs them to the appropriate Minister, which he said is exactly what happened in this case.

The PM also said it was desperate to claim this case was anything further than that, and insists he still has no links to foreign trusts.

However Green Party co-leader James Shaw points out there are two conflicting stories: "The email that was sent to the Minister of Revenue by Antipodes said that the Prime Minister had assured them that their was not going to be a review of foreign trusts, so there is an inconsistency."

"It looks like an example of lobbying by the Prime Minister's personal lawyer on behalf of his own firm but also the foreign trust industry in New Zealand," Shaw said.

Shaw is calling on the Prime Minister to be more up-front about the conversations he had with Antipodes over tax reviews.

Labour's finance spokesman Grant Robertson said the appearance of lobbying efforts for offshore finance specialists shows the appointment of tax expert John Shewan's review of the sector is "wholly inappropriate".

He says an independent inquiry is needed.