The findings were to be presented to the Governor-General by November 12.
Shirtcliff gave evidence at the commission last month via video link from Brisbane. However, the Press cast doubt on some of his qualifications and said Shirtcliff had lived off and on in Australia since about 1970 under the name William Anthony Fisher.
It was also reported he was sentenced to 20 months' jail in 2005 for a Christchurch fraud in which he forged GST receipts to make it look like his failing automotive business was thriving.
A Christchurch family was cheated of about $300,000 in the fraud.
The Press claimed Shirtcliff had been using the identity of English engineer William Anthony Fisher since 1970. He had worked with him in South Africa in 1968 and 1969.
Shirtcliff, 67, supervised the construction of the CTV building until its completion in October, 1987. It collapsed in a 6.3 magnitude earthquake in February last year, killing 115 people.
Last night, Brisbane lawyer David Tucker said his client, who he called Will Fisher, strenuously denied all the allegations made in the media stories.
"We are instructed that the allegations of identity theft are untrue and without any substance whatsoever. Mr Fisher is not available for comment today as he is quite distressed by the unwarranted attack on his integrity."
He said Fisher would answer any reasonable questions over the construction of the CTV building.