ACC has launched an investigation and asked the Serious Fraud Office to examine claims of corruption over the lease of its central Wellington offices.
The lease of the Taranaki St building was negotiated by former ACC national property manager Malcolm Mason, sacked in 2010 after taking a bribe in return for confidential information.
ACC confirmed this week it had started investigating after receiving a letter alleging the Taranaki St deal was "dodgy". Mr Mason declined to comment.
An ACC spokesman said the corporation had contacted the SFO to find out whether the allegations had links to previous investigations of Mr Mason.
The SFO said it had received the information and was assessing it.
The Taranaki St building was vacated in May last year after engineers found it was an earthquake risk.
ACC has not been able to negotiate a buyout of the lease, which has three years to run, and is paying $450,000 a year in rent.
In 2011, Mr Mason admitted taking a $160,000 bribe from businessman Gregory Hutt for the name of a building ACC planned to lease in Whangarei.
Mr Hutt bought the building and later sold it at a profit thanks to the security of ACC's long-term lease.
Mr Mason pleaded guilty to corruption and bribery charges and was sentenced to 11 months' home detention in March 2011.
- © Fairfax NZ News
Rate the Government's progress around drinking laws:Related story: New drinking law a vital step