Labour Party leader David Shearer says list MP Clayton Cosgrove has been absolutely transparent about donations to his 2011 election campaign.
Mr Cosgrove received $17,500 from a company called Independent Fisheries.
That company would have benefited from a member's bill drawn up in 2009 by Mr Cosgrove to allow fast-tracked development of land in earthquake-damaged Christchurch and Kaiapoi.
The MP has denied any connection between the draft legislation and the donation, and that is backed up by his party leader.
Mr Shearer says Mr Cosgrove's bill was drawn up on behalf of more than 100 of his constituents.
He says he has no concerns about the MP's actions and will not be taking the matter further.