Two and a half million foreigners have moved to the UK to work since 2002, National Insurance figures suggest.
NI numbers are issued to those who have not worked in the UK before
The numbers, which include those who may only have been in the UK for a short time, have been getting larger each year, reaching 713,000 last year.
The Home Office stressed these were people coming to the UK to work, and said it now monitored social impact.
But Damian Green, for the Tories, said the "huge" and "accelerating" figures were "extraordinary" and should be cut.
REGIONS WORKERS ARE FROM
New EU countries: 321,00
Asia & Mid-East: 145,000
Old EU countries: 103,000
Aus & Oceania: 33,000
The Americas: 32,000
Non-EU Europe: 16,000
Source: DWP figures on those registering for a National Insurance number in year to April 2007
The shadow immigration minister highlighted the 300,000 workers arriving in the UK from outside the EU, saying that number should be cut.
If not, he said: "The benefits of immigration will be lost among the social and economic difficulties caused by the sheer scale of the current numbers."
Lib Dem home affairs spokesman Nick Clegg said the 16% increase in east European immigrants given National Insurance numbers "confirm that the numbers are considerably higher than the Government first estimated".
He said the Government had "failed to plan adequately both in terms of housing and funding for local services".
But, he said: "It should be remembered that people are only coming to Britain because they are successfully providing services and doing jobs available in the British economy to the benefit of British consumers."
National Insurance numbers are needed by anyone of working age who wants to work legally or claim benefits in the UK. The figures do not include dependents such as children.
FOREIGNERS MOVING TO UK
Source: DWP figures on NI numbers given to foreign nationals each year
The expansion of the EU has been the biggest reason for the increase - 222,000 Polish people were given National Insurance numbers for the first time in 2006/7, bringing the total to 466,000 in the past four years.
That is higher than previous Home Office figures based on the workers registration scheme, which does not include the self-employed.
The National Insurance figures, released by the Department for Work and Pensions, show the vast majority of people coming to the UK to work from across the world are under the age of 35 and 54% were men.
Analysis of the previous year's figure shows that about 16,000 of the foreign workers were claiming out-of-work benefits within six months of getting a National Insurance number.
The 713,00 figure for the latest year is more than double the 349,000 National Insurance numbers allocated to overseas nationals in the year to April 2003.
COUNTRIES OF ORIGIN: 2006/7
Slovak Repub: 28,000
Source: DWP figures on NI numbers allocated in year to April 2007
In that year the largest place of origin for those workers - 114,000 - was Asia and the Middle East, followed by 80,000 from the "old" European Union member countries.
Although the influx of new EU nationals accounts for much of the rise, there has been a rise in numbers from all continents with the exception of Africa.
There are a variety of ways in which immigration is measured in the UK, although there is not one definitive one, and none include illegal immigrants.
These figures do not mean there are now 713,000 more foreign workers in the UK than a year earlier, as the figures do not count those who leave the UK.
A Home Office spokesman said: "The number of National Insurance numbers issued to accession nationals is consistent with Home Office data and shows that people are coming here from the expanded EU to work.
COUNTRIES OF ORIGIN: 2003/4
Source: DWP figures on NI numbers allocated in year to April 2004
"However, there are legitimate concerns about managing some of the effects of migration on communities. We are listening to these concerns.
"That is why we have taken a more gradual approach to opening our labour market to people from Bulgaria and Romania by maintaining restrictions and introducing quotas on low-skilled jobs."
He added: "Last month we had the first meeting of the Migration Impacts Forum, set up to advise the Government what effect migration is having on local communities, particularly with regard to housing, education and crime levels."