Kent could be forced to accept thousands more houses every year under government plans to address what it says is the chronic shortage of affordable homes.

The move to impose higher building targets will put councils on a collision course with the government and is likely to cause friction with MPs.

The new targets have already been condemned by environmental groups who have complained bitterly that they will put even more pressure on Kent’s countryside.

Under the government’s plans, 10,000 more homes would have to be built than councils themselves say are needed.

A revised formula the government plans to use will force councils to give the green light to building programmes if average house prices are greater than four times income.

Indicative figures released by the government show the formula to be used could have a dramatic impact on large parts of Kent with far higher targets than most councils say they need.

The worst affected area would be Swale, with the government saying the yearly target would be 1,054 compared to the 776 the council says are needed.

Thanet would also be affected, with a revised annual target of 1,063 compared to 857 while Ashford would have to accept 989 new homes each year compared to the 825 the council says are required.

In Canterbury, the figure would be 1,098 compared to 825 a year.

Medway would have to accept a figure of 1,665 under the formula. It is under pressure after plans for 5,000 new homes at Lodge Hill in Chattenden.

More modest increases would be seen in parts of west Kent, with Sevenoaks seeing an increase to 698 from 620.

Only one area of the county - Shepway - would see a fall in new houses expected to be built each year, going from 633 a year to 490 a year. But that is only because the government appears to have already taken into account the controversial Otterpool development, which will see 12,000 homes built on land near Folkestone race course.

The prospect of tens of thousands of new homes is bound to cause alarm among councils, many of whom are already trying to resist large developments eating into available land.

The figures were released by the government under its Housing White Paper, designed partly to increase the supply of more affordable new homes.

Housing minister Sajid Javid said the current way of calculating the number of new houses needed was outdated.

“The existing system for determining [housing demand] simply isn’t good enough. It relies on assessments from local authorities according to their own requirements carried out by expensive consultants using their own methodology."

“The result is an opaque mishmash of different figures that are consistent only in their complexity.”

Nationally, the number of new homes needed under the formula would rise to 266,000 annually.

In Kent, it would mean just over 10,000 new homes being built across the county’s 12 districts and boroughs.

Hilary Newport of Kent CPRE said: “This takes no account of local differences. We are very disappointed and it does not reflect the way the housing market works. It is much more sophisticated than that. If this was to deliver more affordable homes, then that would be one thing. But raising the bar like this does not take into account any local differences. This is not good planning - the government should be looking away from the south east.”

Councils have reacted cautiously but are bound to come under pressure to resist even higher targets.

But some MPs are already unhappy at the targets set by councils. Faversham and Mid Kent MP Helen Whately recently intervened in the debate over Maidstone council’s local plan, writing to Sajid David to say she had serious concerns about the targets.