Families of those who died in the CTV building in Christchurch say they want former construction manager Gerald Shirtcliff investigated in light of recent allegations against him.
The multi-storey Canterbury Television building in Christchurch collapsed in the February 2011 earthquake, killing 115 people.
In Australia, the professional engineers body is urgently investigating the registration of a William Anthony Fisher, who Fairfax media says is actually former Mr Shirtcliff.
The Press newspaper has published a story saying Mr Shirtcliff stole the identity of another engineer and faked an engineering degree.
Mr Shirtcliff recently gave evidence by video link from Australia to the Canterbury Earthquakes Royal Commission which is investigating the collapse.
Murray Grant, whose wife Jane Grant died in the building's collapse, says Mr Shirtcliff needs to be held to account.
"He hasn't been very forthcoming, he hasn't been particularly helpful to the inquiry. He's obviously tried to distance himself from it."
Brian Kennedy's wife also died in the collapse and says the latest allegations are yet another revelation in what has become an absolute disaster.
The Royal Commission says the hearing into the performance of the CTV building is complete and will not be reopened.
Engineers Australia says the organisation was investigating William Anthony Fisher before the report in The Press but would not say who or what triggered the inquiry.
The organisation says it is taking the allegations very seriously and will refer the matter to the police if it considers a crime has been committed.