The Serious Fraud Office will now look at the electoral spending of Mayors Lianne Dalziel and Phil Goff, after referrals from police.
A former Christchurch Mayoral candidate John Minto complained that Lianne Dalziel had failed to disclose the indentities of donors who had bought items at a fund raising auction organised by her husband.
At the time Dalziel said she did not think the six donors needed to be declared - but later amended her return and named them.
Checkpoint has been unable to contact Ms Dalziel as she has been travelling.
Mr Goff's office is not commenting. Complainant John Minto tells Lisa Owen we need to change the way we fund campaigns.