Foreign-born workers have accounted for more than half of the rise in employment in Britain over the past year, according to official figures.
The number of foreign-born workers finding employment in the UK has risen by 225,000 to 4.26m over the past year, compared to an additional 192,000 UK-born men and women in work.
Figures from the Office for National Statistics also disclose for the first time that more than 112,000 people who were born in Bulgaria and Romania are already working in Britain, a rise of 14pc on the same period in 2012.
The rise comes amid growing concerns about a new wave of immigration from Bulgaria and Romania next year, when immigration restrictions are being lifted.
The new wave of immigration, which could lead to 50,000 people a year moving to this country from abroad, has led to warnings that Britain is facing an influx of people at an "unsustainable level".
Frank Field, a former Labour minister, a former Conservative minister, have warned that David Cameron must do more to tackle the "elephant in the room" and restrict European immigration.
The MPs, two of the most influential politicians on the immigration debate, have said that draconian action should be taken during period of high unemployment to protect low-skilled British workers.
One in three young people aged 18 to 24 who are not at university or college are currently unemployed or not in paid work.
According to new figures, the number of people working in Britain who were born in countries which joined the EU in 2004, including Poland and Hungary, has risen from 674,000 to 687,000.
The bulk of the new foreign-born workers are from outside the EU, with 46,000 from Africa and 76,000 from the "rest of the world".
Last year, just over a third of the rise in employment in Britain was attributed to people born abroad. In 2011, however, almost 80pc of new workers in the UK were born overseas.
Other figures published by the ONS showed that unemployment had risen for the third quarter in a row, from 15,000 to 2.52m, between January and March.
Wages went up by just 0.4 per cent, well below the 2.8pc level of consumer price inflation.
Mark Hoban, the employment minister, said the Government was "not complacent". He welcomed falls in the number of people claiming jobseeker's allowance and the number of young people out of work.
He also pointed to figures showing an increase in job vacancies for February to April 2013, up 40,000 compared with a year earlier to 503,000 and the highest since the end of 2008.
Mr Hoban said: "Whilst there has been a disappointing increase in the headline rate of unemployment, we shouldn't forget the progress we are making."
Liam Byrne, Labour's shadow work and pensions secretary, said: "We now have definitive proof the Government has simply failed to get Britain back to work."