Up to 640,000 new homes should be built across the South East over the next 20 years, it has been announced.
Tory councillors say the plans fail to address infrastructure requirements
Original proposals to build up to 720,000 new homes were amended at a meeting of the South East England Regional Assembly on Monday.
The new figure is the highest of three options put forward which would see either 25,500, 28,000 or 32,000 homes built every year between 2006 and 2026.
They were drawn up in response to government projections of housing need.
Need for funding
The proposals will go out to public consultation in January although deputy prime minister John Prescott will have the final say on the number of homes to be built.
The assembly, which consists of 111 members including councillors and local representatives, covers Oxfordshire, Buckinghamshire, Milton Keynes, Berkshire, Hampshire, the Isle of Wight, Surrey, East Sussex and West Sussex and Kent.
Paul Bevan, chief executive of the assembly, said: "We think the lowest figure is about the annual rate of building at the moment.
"We're saying to the government we don't want to increase rates of growth above current levels without some clear commitment to extra funding."
Tory county council leaders earlier insisted the highest number of homes that could realistically be built in the period is 510,000 - the draft plan's lowest
They pledged to ensure that no new houses are built without a firm government
commitment to pay for the necessary supporting infrastructure, such as roads, schools and health facilities.
Keith Mitchell, leader of Oxfordshire County Council, said: "Our infrastructure is creaking.
"It won't do for the government to fudge the question of who will pay for the £30 billion of infrastructure investment that building on this huge scale