the UK Government is examining ways to restrict the access of EU migrants to benefits, but has stressed it would act within the law, Downing Street officials have made clear.

Prime Minister David Cameron wants to impose tougher conditions in the wake of work restrictions being lifted on Bulgaria and Romania from January 1.

One suggestion is extending the length of time new arrivals have to stay in Britain before they can claim benefits - from three months to a year.

Asked about reports that Mr Cameron was considering quadrupling the residency period, his spokesman said: "You would expect the Government to be looking at whether there is more that could be done. That process is, as you would expect, going on."

He stressed he was not in a position to say when a decision might be made or what changes might be introduced, noting: "I can't speculate about possible timings or measures."

But any idea the Government would seek to break international rules was rebuffed, with the spokesman insisting: "The Government acts within the law."

Yet any extension to the bar on benefits would potentially set up a clash with Brussels and a row within the Lib-Con Coalition. The European Commission prevents member states from discriminating between their own citizens and those from other EU member states.

Meanwhile, about 8000 Bulgarians could come to the UK when restrictions on their movement in the EU are lifted next year, according to the country's ambassador Konstantin Dimitrov.

He said last night they could not legally be denied access to labour markets once the controls were lifted in January. Asked about how many the UK could expect, he said: "Maybe 8000 immigrants a year judging on tendency for this year."