The delivery of two new Bass Strait ferries, a project marred by delays and cost blowouts, has been hampered by an "appalling lack" of government support, an inquiry has been told.
The larger Spirit of Tasmania ships are yet to begin service, years behind initial estimates, and have a $900 million-plus price tag.
Port upgrades at Devonport in Tasmania won't be ready by the time the first ship is due to start sailing in 2025.
The vessels will have to operate at reduced capacity until the upgrades, estimated to be completed in 2026 at the earliest, are finished.
A Tasmanian parliamentary inquiry examining the project on Tuesday heard from former chairman of ferry operator TT-Line Michael Grainger.
Mr Grainger was sacked by the Tasmanian government in August after pledging to "set the record straight" about reasons for delays.
He told the inquiry his sacking was bizarre and he had always kept the relevant government minister informed about the project.
"I've worked with six premiers and 10 government ministers from both sides of parliament," he said on Tuesday.
"(I) have never witnessed such an appalling lack of support from government as experienced over the previous 12 months."
Mr Grainger said TT-Line wasn't granted access by fellow state-owned company TasPorts to the Devonport berths, meaning geotechnical work couldn't progress.
"We made it clear to our minister in 2022 that we (were) sceptical of the ability to complete our requirements due to the lack of support from TasPorts," he said.
The ships' Finnish builder was paid an extra $81 million by TT-Line in March, while the cost of port upgrades have risen from $90 million to $375 million.
In August, Michael Ferguson relinquished the infrastructure portfolio, saying TT-Line had refused to take responsibility.
"Tasmanians are ... rightfully confused and disappointed the necessary berthing infrastructure has not been adequately prepared in proper time," he said at the time.
Mr Ferguson previously told the inquiry in the lead-up to the March state election TT-Line had informed him the berth upgrades were on track.
Mr Grainger said by that point he had told the government, which sits in minority, the upgrades wouldn't be completed on time.
Labor opposition leader Dean Winter accused Mr Ferguson of misleading parliament and flagged moving a motion against him when the lower house next sits from October 15.
"The evidence presented demonstrates Mr Ferguson was fully aware of and responsible for the biggest infrastructure stuff-up in Tasmanian history," Mr Winter said.
"As shareholder minister and member of the cabinet sub-committee overseeing this critical economic project, it is not appropriate that he remain in those roles.
"The premier must act on Mr Ferguson. If he doesn't, the parliament will have a very big decision to make."
Government MP Guy Barnett told reporters Mr Grainger was entitled to give evidence and noted the inquiry would produce a final report.
