Former Solicitor-General Michael Heron QC has been appointed to investigate allegations three senior earthquake recovery officials tried to use their positions for personal financial advantage.
The officials, from the now-defunct Canterbury Earthquake Recovery Authority (Cera), were accused of trying to arrange property deals through their own company for a finders' fee.
The employees have either stepped down, or been stood down, from their new government roles.
They are Murray Cleverley, who was a chairman of Canterbury District Health Board, and Gerard Gallagher and Simon Nikoloff, who were both with the rebuild entity Ōtākaro Limited.
The State Services Commission had been helping an investigation led by the Department of Prime Minister and Cabinet, but has appointed Michael Heron QC to conduct the separate inquiry, which would cover the men's actions in subsequent government roles.
Mr Heron has carried out investigations for government ministries in the past, most recently into three fishery operations last year.
An interim report will be given to the State Services Commission by the end of February.
The terms of reference for the investigation will look at any actual or perceived conflicts of interest of the former CERA staff members, during their employment at CERA or their subsequent State services employment or governance roles in the State services.
It will look at the management of any such conflicts of interest by the officials and State services agencies.
The State Services Commission has confirmed the men under investigation are Murray Cleverley, who was a chairman of Canterbury District Health Board, and Gerard Gallagher and Simon Nikoloff, who were both with the rebuild entity Ōtākaro Limited.
All have either stepped down, or been stood down, from their new government roles.