Investigations by Parks and Wildlife found that removing two of the river's most well-known vessels - the Harry O'May and Cape Bruny - could cost $1.8 million.

That figure does not include the costs of removing other abandoned vessels such as the nearby Cape Forestier, historic dredge Ponrabbel II, and a yacht that has been submerged in the Tamar since the 2016 floods.

Another boat, which has been sunk opposite Home Point since at least December, is also yet to be pulled out.

PWS told The Examiner it had "investigated options" for managing derelict vessels in waters it manages.

"The cost of removal of the Harry O'May and Cape Bruny vessels, should that management option be pursued, has been estimated to be in the vicinity of $1.8 million," a PWS statement read.

"PWS continues to work with relevant agencies, including the Department of State Growth, Marine and Safety Tasmania (MAST) and the Environment Protection Authority (EPA), to determine the best approach to the management of these and other derelict vessels."

The Tamar River has a long and complex history with abandoned vessels.

Some shipwrecks have sat along the shoreline for decades with authorities lacking the necessary power to remove them.

In March, then-Transport Minister Michael Ferguson promised to table laws this year that would finally hold owners financially accountable for the removal of derelict vessels.

Eric Abetz has since taken the Transport portfolio.

"They'll have provisions that will allow the state - if there is not co-operation from the proper owner - [to recover costs] from those owners," Mr Ferguson said.

"Should the government have to remove the vessel, the laws will provide a power to cover a cost from the last legal owner.

"This calendar year we need to start taking those first steps - in some cases we'll be providing owners with a warning period and it will be in their interests to get moving right away."

Labor stopped short of saying it would back the laws, but Bass MP Janie Finlay said the party supported a healthy estuary.

"The health of the Tamar River is important and Labor is supportive of minimising risk to the environment and other river users," Ms Finlay said.

The promised laws look set to protect the Tamar from future wrecks, but if history is anything to go by, proving ownership of the river's existing shipwreck population will be no mean feat.

Ponrabbel II has been underwater since September, at which time MAST was working to establish the vessel's owner, while the sunken yacht near Home Point has no clear owner.

The bankrupt estate of late shipping identity Les Dick has disclaimed the three vessels tied up outside Tamar Valley Dairy - the Harry O'May, Cape Bruny and Cape Forestier.

PWS has confirmed it is not pursuing any current legal action in relation to these vessels, which have increasingly become a nuisance.

In October 2022 the Cape Bruny was found to be the source of an unquantified oil spill.

The EPA confirmed it is yet to reclaim any of the $145,915 clean-up bill, which included the removal of remaining fuel.

Former car ferry Harry O'May has become a breeding ground for seagulls, leading the Department of Natural Resources and Environment to spearhead five years of experiments aimed at discouraging nesting.

Launceston businessman Errol Stewart said seagull droppings had become a huge problem for nearby businesses.

"They're just an absolute pest," Mr Stewart told The Examiner in November.

"Bunnings is absolutely covered in seagull crap, as is the Good Guys, as is our aircraft hangar - you put a car over there and it'll be covered with seagull crap in 10 minutes."

The Good Guys declined to comment on costs incurred by the problem.

If ownership of the Tamar's abandoned shipwrecks cannot be lawfully established, taxpayers will likely be forced to stump up the costs.

In 2018 the Queensland government announced a $20 million 'War on Wrecks', which pulled 1000 vessels out of the water in four years.

The program sought to recover removal costs from owners "where they can be identified" and disposed of at least four vessels at costs of between $500,000 and $1 million.

One of these ships was Les Dick's former Bass Strait ketch the Defender, which sunk in Townsville in 2015.

Independent MLC Rosemary Armitage said the state government may have to take a similar approach in pulling abandoned vessels from the water regardless of whether costs can be reclaimed.

"If you've got no-one to reclaim it from, at the end of the day it's a community good to clean up the river," she said.

"It's just one of those costs you have to bear and the community bears it in the end - rates and taxes is where all the money comes from.

"But you can't just leave it there because you don't know who owns it - it needs to come out."

Ms Armitage said in some instances it was better to "write things off" than pursue justice through the courts.

"Sometimes it's cheaper just to go and do it, clean it up," she said.

"By the time you've paid silks, lawyers, all these people to go to court - you might win on paper but it might cost you more to win than to just go and do it.

"We all want to clean the Tamar River up - let's get rid of these sunken hulks so they can't cause any problems to people in the future."