Consultants had six weeks over the Christmas period to develop a business case for Victoria's now-cancelled 2026 Commonwealth Games bid, a process that would usually take years.
They were unable to visit venues because of the short turnaround time and confidentially agreements stopped them speaking to potential suppliers or partners, Ernst and Young partner Dean Yates told a parliamentary inquiry on Tuesday.
Mr Yates said the timeline from mid-December 2021 to the end of January 2022 was "particularly tight" and there were significant limitations, but all risks were comprehensively outlined.
Victoria withdrew from hosting the 2026 Commonwealth Games in July after former premier Daniel Andrews claimed the forecast expenses had nearly doubled to up to $7 billion.
Consultants from Ernst and Young, DHW Ludus and MI Associates were involved in the report and all stood by their work when questioned at the inquiry.
"The highly confidential nature of this engagement meant that no fieldwork, such as formal inspection of the potential venues ... could be undertaken," Mr Yates said.
"Nor could any consultation take place with any potential suppliers, partners or other parties."
He said it was widely understood costings in the report would need to be validated and tested.
Mr Yates said the bid process usually took years, but consultants had a six-week timeline.
He said he was surprised the event was scrapped, because Ernst and Young was not involved in providing the updated cost estimate later used by Mr Andrews to cancel the Games.
Department of Jobs, Skills, Industry and Regions secretary Tim Ada fronted the inquiry for a second time on Tuesday.
He said Department of Premier and Cabinet secretary Jeremi Moule informed him the government was considering dumping the Games on June 19 and told Mr Ada to not tell the minister he was working under.
Former Commonwealth Games legacy minister Harriet Shing was accused of lying during her October inquiry appearance after suggesting she was kept out of the loop.
She was advised three days later on June 22 by then-Commonwealth Games delivery minister Jacinta Allan, who replaced Mr Andrews as premier in September.
"I remember seeking assurances that Minister Shing would be told by the government and I assumed that would be happening contemporaneously with me being told," Mr Ada said on Tuesday.
He denied the decision for him not to tell the minister was unlawful and not reasonable, as he was following directions provided by the premier.
Ms Allan on Tuesday said Mr Andrews requested her to provide the information to Ms Shing.
"The then premier asked me to provide that information to Minister Shing a mere number of days after he had asked his department to seek that advice," she said.
A submission to the inquiry from Athletics Australia claimed the cancellation hurt athletes and the nation's reputation, causing "immeasurable" upheaval.
President Jane Flemming and director Steve Moneghetti said they had not sought an apology from the Victorian government but wanted infrastructure meant to be built for the Games to go ahead.
Australian Associated Press