An architect who said the government's plans for the Thames Gateway were "pathetically unambitious" has called for an environmentally friendly scheme.
Sir Terry Farrell says he has taken a holistic view of the Gateway
Sir Terry Farrell, who has produced a detailed plan for the area - set for 120,000 new homes by 2016 - said the government had given no clear vision.
"We could create something that is green through and through," he said.
Gillingham's Labour MP Paul Clark said money had been made available for "greening the Gateway".
The Thames Gateway spans a 40-mile stretch of east and south-east London and parts of Kent and Essex.
It was announced by Deputy Prime Minister John Prescott three years ago as a way of attempting to meet the south's long-term housing needs.
A discussion document leaked to the BBC last month revealed large areas of the Gateway could be allowed to flood as part of an "estuary park".
But Sir Terry, who designed London's new Home Office building, the MI6 headquarters and Charing Cross station, said the area should be designated a national park, with a bridge spanning the Thames estuary.
"By standing back, as I have been able to do, I can see it holistically," he told BBC South East Today.
"Everyone is now realising that, not only do the countryside and our national parks have to be green, but so do the cities and towns where we live."
He believes the Gateway plans include too few homes and that they are in the wrong place.
"I don't think the shortage of homes should be met by putting commuter dormitory towns in Kent and Essex," he said.
"They should be located within London to reinforce the infrastructure that is there at the moment."
Mr Clark, who is Mr Prescott's Parliamentary aide, said: "I agree entirely with Sir Terry.
"We need to have town and cities within Kent, London and south Essex that are green and where people want to live.
"But one of the big issues is about having enough homes for the existing population."
He said money had been made available for "greening the Gateway" with projects such as Medway's Ranscombe Park.