Two new Bass Strait ferries plagued by delivery delays and cost blowouts have hit further trouble, with technical issues identified on both ships.
The Spirit of Tasmania vessels aren't expected to be in service until late 2026, years behind schedule because of a failure to build a berth for the ships.
Spirit IV has been sitting in Scotland since December, while Spirit V is being put through sea trials by its Finnish-based shipbuilder.
Technical issues on both ships in relation to their liquefied natural gas systems have been identified, the Tasmanian government said on Wednesday.
The issue was discovered as part of Spirit V sea trials, Transport Minister Eric Abetz said.
Spirit IV was due to leave Scotland for Hobart on Monday, to undergo its final fit-out, but it will now remain there indefinitely for further assessment and repairs.
"The government is awaiting further details in relation to a new expected departure date (from Scotland)," Mr Abetz said.
"It is understood that this work will take some time. The ship will be relocated to Hobart as soon as possible for final fit-out."
Repair costs will be covered under warranty with shipbuilder RMC, Mr Abetz said.
Delivery of the two larger vessels, which cost more than $900 million, has been dubbed one of the greatest infrastructure stuff-ups in Australia's history.
The ships were due to be delivered to Tasmania in late 2024, but required berth upgrades at Devonport aren't expected to be finished until late 2026.
Industry and tourism bodies keenly awaiting greater capacity of the new ships have lashed the government for their handling of the project.
The saga forced Tasmania's deputy premier Michael Ferguson to relinquish his portfolios and prompted resignations at government businesses in charge of the ships.
Projected costs for the Devonport berth in May rose from $375 million to $493 million, well beyond the initial $90 million estimate.
