Labour MP Clayton Cosgrove says he has nothing to hide over a donation from a "mate" who would have benefited financially from legislation he drafted.

Questions have been raised after it was revealed Mr Cosgrove accepted $17,500 in donations from Independent Fisheries, one of several landowners that would have benefited from a bill aimed at easing restrictions on residential developments in the Christchurch International Airport and Cranford Basin areas.

Mr Cosgrove drafted the legislation in June 2009 but it was never drawn from Parliament's member's bill ballot and he let it lapse after the first Christchurch earthquake in September 2010.

He accepted a $3000 donation from Independent Fisheries in December 2007, a $2500 donation in November 2009 and a $15,000 donation in June 2011.

He confirmed Independent Fisheries chief executive Mike Dormer was a longstanding friend.

"I know his family, he knows mine, he's one of the biggest philanthropists in Christchurch, a highly respected businessman," Mr Cosgrove said. "I'm proud to say I'm a mate of his. I think you'll find most people in Christchurch know we're mates."

Mr Dormer said last night he was unable to comment but would be issuing a statement today.

He referred Fairfax to a statement provided to TV3's The Nation, in which he said the Christchurch Airport Protection Bill was not initiated by Independent Fisheries, nor did it make any payments to Mr Cosgrove in connection with that bill.

It also stated that Independent Fisheries had a long history of funding political parties.

If the bill had gone through, Independent Fisheries, along with other landowners, would have made a financial windfall.

Mr Cosgrove said he had been upfront from the beginning. "What would be inappropriate and a bad look is if I hadn't been open and honest and transparent about the donations and I've always, in the appropriate way as the law requires, declared donations.

"There is no conflict of interest because I declared these things; I was open and honest about it."

Mr Cosgrove said his bill would have benefited more than 100 landowners, not just Independent Fisheries, and the impetus for it had come from a public meeting, out of which a working group of landowners and local body politicians was formed.

"I was representing probably well over 100 individuals, mums and dads who wanted to subdivide the front lawn, to bed and breakfast owners, to entities and property developers ..."

Mr Cosgrove said that after the bill lapsed in 2010, he wrote to Earthquake Recovery Minister Gerry Brownlee in August 2011 about the matter and said Mr Brownlee had adopted part of his proposal.

Otago University faculty of law professor Andrew Geddis said disclosing a donation did not remove a conflict of interest.

"All a declaration does is let us see that two things have happened – that he put forward a bill and, secondly, he received a fair chunk of money from Independent Fisheries."

The first question then was whether any illegality was involved – which no one was suggesting to be the case – and the second was whether MPs should "even put themselves in a position where those questions are asked".

"Just because he did the legal thing doesn't mean he did the right thing, in terms of how we expect our MPs to behave. Obviously we expect our MPs to follow the law but that's the bare minimum."

Last night, Labour was standing by Mr Cosgrove, and said the only thing he was guilty of was helping his constituents.

Deputy leader Grant Robertson said Mr Cosgrove had done what Labour expected of its MPs by trying to help "hundreds of constituents".

"He did what Clayton does as a straight-up MP - worked hard on their behalf, tried to find a solution for them ... he was motivated by finding the best outcome for his constituents."

But Prof Geddis said there was a question mark over whether MPs "should be using the full force of Parliament to try to get a win for some of their constituents over others".

- © Fairfax NZ News