The Serious Fraud Office has confirmed it is looking into the election expenses of Christchurch mayor Lianne Dalziel.
A short statement has just been released by the authority confirming it has received a police file on the mayor.
"The Serious Fraud Office has received a referral from NZ Police in relation to Lianne Dalziel's election expenses," the statement reads.
"The SFO will be assessing the matter and has no further comment at this time."
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The development comes after the Christchurch City Council's electoral officer was asked to investigate why Dalziel has only revealed the identities of six people who each donated more than $1500 to her campaign.
They donated through an auction her husband, Rob Davidson, ran.
Dalziel only declared the amount that came from him and only declared the other contributions after pressure from mayoral candidate John Minto.
Dalziel has blamed her husband for the lack of transparency, after she followed his advice that he did not believe the other donations had to be declared.