Attorney-General Chris Finlayson should be stood down for repeatedly failing to declare his directorship of a company in Parliament's Register of Pecuniary Interests over the last four years, Labour MP Trevor Mallard says.

Mr Finlayson helped set up Te Puhi Trustee No 2 Ltd - which is the corporate trustee for Mr Finlayson's friend and former Creative New Zealand chairman Peter Biggs' family trust - in 2006.

Since then Mr Finlayson had been listed as a director and shareholder of the company, a fact which Mr Mallard yesterday said had not been declared by him in the Register of Pecuniary Interests.

Parliament's Standing Orders say MPs must give the name of each company of which they are the director, or in which they have a more than 5 per cent stake.

By omitting his directorship of Te Puhi, Mr Finlayson had made false declarations, Mr Mallard said.

"When you're Parliament's chief law officer then you're expected to have all your declarations as true."

Mr Mallard believed the matter was serious enough that Mr Finlayson should stand down as Attorney-General and should be out of Cabinet.

But Mr Finlayson said he had no pecuniary interest in Te Puhi or the underlying family trust.

"Accordingly, I did not declare the directorship of the corporate trustee for the family trust as a pecuniary interest."

However, he confirmed he was seeking advice from the Registrar of Pecuniary Interests as to whether a directorship with no pecuniary interests should be declared and he was expecting an answer today.

"It may turn out that he should have declared that, we just don't know," a spokesman for Mr Finlayson told the Herald.

Mr Mallard said the relevant rules were clear and not for interpretation.

"I would have thought frankly the Attorney-General is someone who should be able to understand what's written down in black and white."

In 2006 then Attorney-General David Parker resigned amid allegations he'd filed false returns to the Companies Office over several years. He was reinstated to Cabinet after being cleared of any wrongdoing within three months.