Michael Hocking, chairman of statewide lobby group Taxed Out, said the introduction of the growth areas infrastructure contribution last June had dampened the rural property market.

"Definitely people have not been selling land and not wanting to buy land because the Coalition had promised they would change the tax."

Planning Minister Matthew Guy announced last week the Coalition government would introduce a bill to amend the GAIC so it was payable only when land was developed for housing.

Under Labor's GAIC plan landholders in the growth area - which now includes much of Casey - would have had to pay $95,000 a hectare when they sold land, regardless of whether they sold to a developer.

Mr Hocking, a partner in the Oakwood Riding School in Clyde, said the GAIC had caused great distress, particularly to elderly farmers who had seen their retirement plans threatened.

About 500 landholders were involved in the Taxed Out campaign, lobbying the Labor and the Coalition before last November's election.

Mr Hocking said the aim had always been to change the timing of the tax so it was payable when the land was subdivided rather than block it altogether.

"We weren't asking them to go out on a limb. They got the money eventually and they will probably get it sooner because the disincentive has been removed."

Taxed Out member Lido Casali told the Weekly he believed the controversial tax had spelt the end of the previous Labor government.

Mr Casali, who owns 13 hectares in Cranbourne South, spent many months letterboxing against the tax in marginal Labor seats in the south-east before the election.

"I was prepared to do almost anything legal to stop this horrible, horrible tax," he said.

"We already have a land tax, capital gains tax and council rates. With this tax, I feel like they want me to go. I resent it."

He said the big breakthrough came after months of lobbying when the Coalition made a commitment to amend the tax.