A complaint about John Banks' election return for the 2010 Auckland mayor contest has been referred to the police by the Auckland Council electoral officer, as required under law.
The complaint was made this week by Labour MP Trevor Mallard.
Mr Banks filed his return on December 9, 2010. Among his total donations of $948,937 he cites an anonymous donation of $15,000.
The successful candidate, Mayor Len Brown, declared a $15,000 donation from Sky City.
The Herald reported Sky City on December 13, 2010 saying it had given $15,000 to both Mr Brown and Mr Banks.