An Australian current affairs television programme says convicted fraudster Gerald Shirtcliff, who oversaw the construction of the CTV building in Christchurch, worked on dozens of buildings using another man's identity.
The central city building collapsed after the 22 February quake in 2011, killing 115 people.
Mr Shirtcliff is being investigated by police in New Zealand and Australia for identity theft and misrepresentation.
The 60 Minutes programme says he worked as an engineer on dozens of buildings in Australia using the stolen identity of British engineer William Fisher whom he met in South Africa more than 20 years ago.
It says Mr Shirtcliff has been working as a civil and structural engineer in Australia and New Zealand using that stolen qualification.
The real William Fisher, who lives in England, told the programme that Mr Shirtcliff stole his degree when they worked in South Africa.
Gerald Shirtcliff initially refused to give evidence when called by the Royal Commission investigating the CTV collapse, but later did via a video link from Brisbane.
It emerged on 60 Minutes that he also worked on a 33-storey building in Sydney's King's Cross.
The programme also interviewed the New Zealanders who had been been defrauded by Mr Shirtcliff and others who have been victims of intellectual property theft.
The Zust family in Queenstown lost their life savings after buying an auto repair business from Mr Shirtcliff 15 years ago.
Eric Zust says he lost a house, land, shares and a business because of Gerald Shirtcliff and it has been the ruination of his family.