The Australian government needs to acquire the Aurora Australis to deliver essential food and supplies to Norfolk Island, says the Australian Maritime Union.
The ship is now retiring after finishing its final voyage supplying Australia's Antarctic base.
Norfolk Island had been experiencing major shortages in retail supplies even before the impact of the global Covid-19 pandemic.
The island's supplies were hard hit when one vessel was taken off the run, while a lack of harbour facilities means Norfolk cannot unload containers.
There has since been a reliance on air freight, which has been massively reduced due to the coronavirus.
The union said the Aurora Australis was uniquely suited to addressing the Norfolk crisis.
It said not only did the ship have the capacity to carry 1790 cubic metres non-containerised break bulk cargo, along with an additional deck capacity for containerised freight, but it had three decades of experience delivering supplies to remote locations.
The vessel can also carry large quantities of fuel.
The union's assistant national secretary Ian Bray, said the vessel should be urgently acquired by the Australian government, with an initial mission to deliver essential supplies to Norfolk Island.
"There are very few appropriate vessels capable of delivering break bulk cargo to remote locations, but the retirement of the Aurora Australis provides a unique opportunity to acquire a ship that is perfectly suited to Norfolk Island's unique needs."
Earlier this week, Air New Zealand said it would continue to provide two services a week to Norfolk Island, one from Brisbane and one from Sydney.