First-time Tasmanian home builders will be eligible for an increased state government grant of $20,000 under a revised scheme written into the upcoming budget.

Backdated to January, the grant will stretch through until July 2017 and is expected to generate about $175 million worth of building activity across the state, Treasurer Peter Gutwein said.

“We want the confidence we are seeing in the construction sector (to) continue, and that’s why we are supporting the sector through the support for first home builders,” Mr Gutwein said on Wednesday when announcing the doubling of the previous $10,000 grant which was due to expire in July.