The federal government has offered up ex-HMAS Darwin to be scuttled in Skeleton Bay for use as tourist attraction.

But Treasurer Peter Gutwein said the capital cost of $12.5 million to scuttle the vessel and an estimated $600,000 a year to maintain the site made the project financially unviable.

He said the wreck would have created an anticipated 36 jobs in the tourism and hospitality sector but cost the government $330,000 per job.

"On that basis, the economic case does not stack up,” Mr Gutwein said.

"As a government, we would rather be spending that money on health or education or other infrastructure investment which would provide a better return than what the dive wreck can."

Liberal Senator Jonathon Duniam said the government’s decision was a blow for the St Helens community.

“We are disappointed that the Tasmanian Government has decided to decline the offer of this dive wreck having willingly bid for the vessel not so long ago and all the work the community have put into securing the vessel,” he said.

St Helens Chamber of Commerce president and dive operator, Peter Paulsen, said the wreck could have provided decades of financial benefit.

"This is a huge disappointment and there's a real sense of loss for what might have been,” he said.

"I still actually believe that this is a perfect fit for this backyard.”

Break O’Day mayor Mick Tucker said the wreck would have provided the region with a point of difference to other tourism destinations.

“(The project has) been an emotional part of our community for quite some time,” he said.

"I respect the government for the decision its made and I understand the reasons why it has made it.

Campaigner against the wreck, Lesa Whittaker, said she was elated by the decision.

"All I can say is that common sense has prevailed,” she said.

Tourism Industry Council Tasmania chief executive Luke Martin said he agreed with the government’s decision and that the money would be better spent elsewhere.