Developers are submitting plans to build thousands of new homes on green belt land in the Ashton Vale – despite the fact the Government's planning blueprint for the area has yet to be published.

Bosses at Baker Associates, who are the planning consultants for Land Trust – the developers behind the multi-billion pound scheme – say it is probable an outline planning application will be submitted this month.

The application is for 9,500 new homes to be built on hundreds of acres of green belt land between the A38 at Dundry near the Barrow Tanks, right down to the A370 Long Ashton bypass. The proposed new development, expected to cost about £2.5 billion and create a town the size of Clevedon, would be called Ashton Park and would form part of the south-west Bristol urban extension.

The move to submit an application comes despite the Government putting on hold the publication of the Regional Spatial Strategy (RSS) – the official planning blueprint being drawn up for the South West.

The RSS was launched last year in response to a Government directive which said thousands of new homes needed to be built across the South West to cope with the growing population.

The strategy, led by the Regional Assembly, identified the swathe of green belt land on the slopes of Dundry and Ashton Vale as a potential area for growth.

The publication of the RSS was expected last month, but this was put on hold following a legal case involving the east of England version of the document.

Baker Associates chief executive John Baker said: "It is probable that we will be submitting a planning application for Ashton Park this month. There is a proposal in the draft RSS for a development of this kind."

Ashton Park will straddle the borders of Bristol City Council and North Somerset Council and both sets of planners will have their say on the outline planning application.

North Somerset Council is objecting to the RSS on the basis the scale of the development is too large.

Campaigners say they are angry plans have been put forward when the RSS has yet to be published.

Members of the Dundry Residents Action Group (DRAG), set up to fight developments in Ashton Vale, said the application was premature.

DRAG spokeswoman Debbie Nicholls said: "It is outrageous that the developers are planning to put forward an application on land that has been designated as green belt and protected for the last 60 years."

"The RSS has yet to be published and it is premature to submit any application until this happens.

"Unless they can prove exceptional circumstances, applications should not be submitted on green belt land.

"We have called on The Minister for Communities and Central Government through the Prime Minister to withdraw the South West Regional Spatial Strategy and make a renewed and irrevocable commitment to the retention of the current greenbelt."

If the Ashton Park development gets the green light it will have a secondary school, five primary schools, two district centres with a number of shopsincluding a food store, a community centre and a business park.

As well as the thousands of construction jobs involved in creating the new town, there will be about 7,000 permanent jobs for local people, about half in the shops, schools and other facilities, the rest at the business park.

Two other major features of the project are the creation of a new high-speed bus link with the city centre – and hundreds of acres of parkland, including water features and a green corridor through the whole development.

It is hoped that eventually this link will be extended out to Bristol International Airport.

The Ashton Park development will not be complete for perhaps another 20 years, but, if plans are approved, work on the first homes and the infrastructure – roads, drains, schools, shops, libraries – could start next year.

The first residents could be moving in from 2011 and the different neighbourhoods are expected to spring up over the next two decades as various developers embark on their parts of the project.

North Somerset Council spokesman Nick Yates said: "If someone wants to submit a planning application, they can. We will examine it in the normal way."