Voters alarmed at plans to expand the size of Norwich are being urged to exert maximum pressure in forthcoming council elections to ward off controversial plans for more than 37,000 homes in and around the city.

Planning inspectors last week gave the green light to the so-called joint core strategy covering the greater Norwich area, which would pave the way for developments such as the ecotown at Rackheath, the Long Stratton bypass, and the Norwich northern distributor road (NDR).

Supporters believe the growth plans will help deliver new homes and jobs in a properly phased way, and not leave the area vulnerable to developers making speculative applications. But critics warn that the plans would effectively create a new town the size of Thetford to the north of Norwich in the area between the city and the Broads, which they fear would destroy the character of the area.

Meanwhile, campaigners fighting the NDR plans said funding uncertainties meant there were fresh doubts about the scheme and welcomed suggestions by the inspectors to test alternative schemes in the meantime. James Frost, director of Norfolk Campaign for the Protection of Rural England, said the inspectors' findings did not mean that the growth plans were automatically a done deal and with council elections due in Norwich, Broadland, and South Norfolk on May 5 voters could send a clear message to local politicians about when they think of the plans.

'We don't feel the public have really understood what's coming,' Mr Frost said. 'It's a megashift, with 37,000 homes, you are talking about 100,000 people to address a genuine housing need of 5,250. It doesn't add up. You are basically building a town the size of Thetford between Norwich and a national park at the Broads. when you say it to people in those terms, they cannot believe it.

'What we have is a high-level political ambition to make Norwich a city the size of Nottingham, that nobody really wants. All of these councils are going to come up for election in May, and they are going to have to say whether they agree with this level of growth or not. It's not too late; people can lobby their councils not to adopt it.'

Meanwhile, Denise Carlo, chairman of the environmental transport umbrella ogranisation, the Norwich and Norfolk Transport Action Group said that despite supporting the growth, planners had expressed doubts as to whether the NDR would be built.

'Environmental groups and developers put forward separate proposals for single carriageway inner link roads as part of an integrated sustainable transport package,' she said. 'We are confident that alternative solutions will be found as developers have said they do not want to spend money on major road infrastructure.'

However, she said the strategy did have some positive transport elements.

'We are also pleased to see firm proposals in the strategy for a network of bus rapid transit corridors and core bus routes,' she added. 'This is the outcome of strong lobbying by environmental groups and the Green Party Group on Norfolk County Council, prompting the Department for Transport to make delivery of sustainable transport measures a condition of NDR programme entry.'