The Green Party is arguing the Prime Minister needs to be up front about his connections to the trusts sector.

An email chain suggests John Key personally told his lawyer, who works for trust specialist Antipodes, a crack-down on the trusts industry by Inland Revenue in 2014 wouldn't go ahead.

Co-leader James Shaw told Jack Tame the emails show Mr Key's lawyer then lobbied the Minister for Revenue at the time, Todd McClay, to ditch the IRD review of the sector.

He says there was a series of emails and meetings between members of the foreign trusts industry, the Minister and senior officials - and it ends with no review of foreign trusts.

LISTEN TO JAMES SHAW'S FULL INTERVIEW WITH JACK TAME ABOVE