Today, Mr Shirtcliff, who was convicted of GST fraud in 2005 and was jailed for 20 months, claimed "limited involvement" with the 1986 project to build the Madras St structure, because it was a "straightforward job".
He said he did not visit the CTV site regularly, leaving responsibility for the "relatively straightforward job" with experienced site foreman Bill Jones.
"I was on site once a month, at most," he said.
"The work was repetitive - each floor was the same as the floor below."
Mr Shirtcliff said he could not recall any problems with the construction, or any issues with the city council, and was too busy with other projects to keep checking on the CTV site.
After rejecting claims he was attempting to "distance" himself from the ill-fated building's birth, questioning turned to his shady background.
Mr Zarifeh asked Mr Shirtcliff what work experience he'd gained while living in South Africa prior to 1986 and what surname he went by.
Mr Shirtcliff denied going by Fisher while he was there, but later contradicted himself by saying: "I've worked everywhere else in the world under Fisher except New Zealand."
Asked why he had changed his name to Fisher, Mr Shirtcliff claimed it was a personal matter following "family issues" 40 years ago.
He admitted that he was extradited from Australia to New Zealand to face a GST fraud trial, on which he was convicted and jailed.
But he rejected claims he cooperated with the royal commission only after being shamed in the media.
"I never said I wouldn't cooperate - ever," he said today, adding he had been in prior communication with commission officials.
His Australia lawyer - who flanked him during the video conference - then interjected to object to his client having "his credit impeached".
But commission chairman Justice Mark Cooper said questions surrounding credibility were "perfectly legitimate" given his testimony is contested by other witnesses.
Mr Shirtcliff denied he could have done more to ensure the CTV Building met correct specifications, saying: "I did what I was required to do at the time."
He further rejected claims he was responsible for supervising construction, the site foreman and sub-contractors.
Earlier today, his boss, Michael Brooks, managing director of Williams Construction Ltd which won the contract to build the CTV Building for local property developer Neil Blair, said he was disappointed with Mr Shirtcliff's work.
'He (Shirtcliff) just wasn't up to the job, it's as simple as that," Mr Brooks said.
His concerns with Mr Shirtcliff related to his failure to provide supervision on site which Mr Brooks agreed could have resulted in construction issues.
Williams Construction development manager Tony Scott understood Mr Shirtcliff visited the site every day.
"I don't see how he could possibly have done his job as construction manager by attending the site once a month. It would've been impossible to do his job properly," he said.
The hearing continues.
