The Serious Fraud Office says it has commenced separate investigations into donations made in relation to the Auckland and Christchurch mayoral elections.

The SFO has not released any further details.

Part 1 of the Serious Fraud Office Act 1990 provides that the SFO may act where the Director "has reason to suspect that an investigation into the affairs of any person may disclose serious or complex fraud".

Part 2 of the Act provides the SFO with more extensive powers where: “…the Director has reasonable grounds to believe that an offence involving serious or complex fraud may have been committed…”

Information carried by Newshub says the SFO received a complaint last month about donations from Christchurch mayor Lianne Dalziel's supporters during the 2019 mayoral election.

It says the SFO also received a police referral in relation to Auckland Mayor Phil Goff's election expenses.

"At the time, Goff said he had no knowledge of any irregularities while Dalziel said she only heard about the complaint through the media," Newshub says.