The Serious Fraud Office has launched a full-blown investigation into the property management of the Accident Compensation Corporation.
The SFO received a complaint from ACC on Tuesday and carried out an initial review of the material provided.
The investigation will focus on the renovation costs and lease arrangements over recent years for about 12 ACC branch offices.
One person who worked at the corporation's head office in Wellington has already been sacked.
ACC Minister Nick Smith says as far as he is aware, that is the only person under investigation.
Dr Smith says no timeframe to complete the investigation has been set, as the SFO should not be put under pressure.
A formal review of ACC's investment portfolio is also under way, but Dr Smith says he is not aware of any untoward practices in that area.
