UK Prime Minister David Cameron has brought forward plans to tighten the country's welfare system for EU migrants as restrictions are lifted on Romanian and Bulgarian workers.

From 1 January, 2014, EU citizens must have lived in the UK for three months before they can claim out-of-work benefits, compared to several weeks as it currently stands.

Benefits will also be removed from EU jobseekers who have "no job prospects", said the government, and there will be a year-long re-entry ban for deported migrants who could not find work.

There are concerns among parts of the British public of an influx of Romanian and Bulgarian immigrants when EU limits on the two states are relaxed in January. Cameron has said he wants to crack down on "benefit tourism" by tightening up the UK welfare system.

"As part of our long-term plan for the economy, we are taking direct action to fix the welfare and immigration systems so we end the 'something for nothing culture' and deliver for people who play by the rules," said Cameron.

"Accelerating the start of these new restrictions will make the UK a less attractive place for EU migrants who want to come here and try to live off the state.

"I want to send the clear message that whilst Britain is very much open for business, we will not welcome people who don't want to contribute."

Polls in Romania and Bulgaria have shown few intend to travel to the UK when the restrictions are lifted. Both countries' diplomats in the UK have predicted just 35,000 will seek work here, because their own improving domestic economies offer a better incentive to stay put.

However, EU statistics show the number of jobless Romanians and Bulgarians lifted in October. Eurostat, the statistical information arm of the EU, said the number of jobless people in Romania rose to 736,000, up from 733,000 in September and 682,000 a year ago.

The amount of people in Bulgaria out of work also increased in October to 449,000, a small jump from 445,000 the month before.

Labour attacked Cameron for taking too long in bringing about the welfare changes.

"Labour called for these benefit restrictions nine months ago. Yet David Cameron has left it until the very last minute to squeeze this change in," said Yvette Cooper, Labour's shadow home secretary.

"Why is the Government leaving everything until the last minute and operating in such a chaotic way? Three weeks ago [Home Secretary] Theresa May told Parliament she couldn't restrict benefits in time, now the Prime Minister says they can.

"They wouldn't be on the run from angry Conservative backbenchers if they'd listened to us nine months ago."