The Tasmanian Greens want Launceston's outdated water and sewerage system to be fixed with a government windfall.

State treasurer Peter Gutwein released a Revised Estimates Report this week showing Tasmania gained an additional GST boost worth $127 million, as well as and extra $150 million worth of conveyancing duty and land tax from its property market.

Greens Leader Cassy O'Connor says that with the budget in surplus, funds should flow to TasWater to upgrade Launceston's water and sewerage system infrastructure.

“It's good to see the state is showing signs of recovery after the 2008 global financial crisis, but instead of talking credit for this windfall and putting it away into an election money basket, the Liberals need to commit to investing it in Launceston's water and sewerage,” she said.

“Now they've got the cash it's one of the most critical infrastructure issues this state is facing and it needs to be dealt with.”

TasWater estimates it will cost over $2 billion to fix infrastructure over the next decade.

The Treasurer says the windfall will be spent on essential services.

“We're in the process of developing the coming budget, that will be released in around three months time and the Government focus will be on ensuring we invest where Tasmanians most need it,” he said.