Last-minute lobbying against the planning gain supplement intensified this week at the Labour party conference in Bournemouth.

The government is expected to make a final decision on whether to push ahead with the controversial levy in the pre-Budget report in mid-October. It has outlined four alternatives, on which it is canvassing views.

John Slaughter, director of external affairs at the Home Builders Federation, said: “We are working to put together a counter-proposal. We need to be supported by as wide a cross-section of the industry as possible.”

A fortnight earlier, Richard McCarthy, the communities department’s director general, warned that “time is running out” to change ministers’ minds about the levy.

The British Property Federation has also been studying the impact of the alternatives to the planning gain supplement (PGS).

David Orr, National Housing Federation chief executive, said housing associations had doubts about the PGS.

He said: “It will be a bureaucratic nightmare and slow down the pace of development.”

The Local Government Association, which represents English councils outside London, is divided. Its officers are sympathetic to the levy but council leaders are less keen.