But the success of the HomeBuilder scheme has also led some Warrnambool builders to call for it to be extended a year.

The scheme offers grants of up to $25,000 to help eligible people to build a new home or substantially renovate, with an aim to boost building work during the pandemic.

GJ Gardner Warrnambool director Andrew Womersley said the scheme, announced in early June, had doubled the franchise's home building inquiry.

"We are now getting 70-plus lead inquiries a month," he said.

Mr Womersley said the business had signed contracts with four home builders eligible for the grant.

"Two of those are a direct result of people learning about the grant," he said. "It was about 'we don't want to miss out'."

Landowners have until December 31 to sign a contract, but construction must commence within three months of signing.

Master Builders Australia chief Denita Wawn is calling for the government to extend the grant 12 months, tipping that home building activity will fall 27 per cent this financial year.

"This will be calamitous for many of the nearly 370,000 home building businesses that are vital to local economies and communities throughout Australia unless the Government steps in with extension of HomeBuilder and other stimulus measures," Ms Wawn said.

Mr Womersley backed the call for a stimulus extension.

"If they had a longer period in regards to when the contract can be signed and still be eligible, that might take a little bit of the rush out of it," he said.

"I think it is a real plus to keeping our economy rolling."

He said in Warrnambool there was a limit on the land available and transferring land titles slowed opportunities to access the grant.

"A lot of those more difficult to build on blocks that have sat left behind in subdivisions ... they are selling, the grant is going to clean up vacant blocks," Mr Womersley said.

Warrnambool builder Stephen O'Keefe said he was concerned construction jobs could plateau in the next 18 months, but had not seen any sign of a slowdown yet.

"We have been quite busy," he said. "We were seeing people who were in a big hurry to commence a project with the stimulus, but they seemed to be struggling to find a builder."

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