Australia's $528 million Antarctic icebreaker could be forced to find a new home after a federal government ultimatum over slated upgrades to its Hobart base.
Federal Environment Minister Tanya Plibersek has raised concerns about the proposed cost and "stalled negotiations" surrounding upgrades at Macquarie wharf six.
In a letter to Tasmanian Premier Jeremy Rockliff, Ms Plibersek said the wharf's development was a fundamental requirement of Hobart remaining the icebreaker's home.