Almost two million foreign migrants have moved into the West Midlands since 2002, raising fears that council services are in danger of being overwhelmed by population growth.
Figures released by the Department for Work and Pensions show that 1,822,110 non-UK citizens settled in the region and applied for National Insurance numbers in the four years between 2002 and 2006.
The influx rose sharply in 2004, following the enlargement of the EU to take in eastern European countries.
The 1.8 million increase is equivalent to one-third of the region's 5.3 million population.
In Birmingham during the four-year period, 38,000 National Insurance numbers were issued to foreign workers - equivalent to more than five per cent of the city's economically active population.
In Coventry the figure was 15,010 - again about five per cent of the working population.
The statistics reflect a national debate about the impact of EU enlargement, with local government leaders across the country warning that they are not receiving sufficient Government funding to meet increased demand on housing, education and social services.
There are fears that three years of low council tax rises in Birmingham may be coming to an end, as the council struggles to find the money to provide services for the newcomers.
The Local Government Association has warned of average council tax rises of six per cent next year. Bills rose by only 1.9 per cent in Birmingham this year, by 2.8 per cent in 2005 and by 1.5 per cent in 2004.
The increases represented a 37p a week rise for the average Band D property in 2006, 50p in 2005, 28p in 2004, 79p in 2003 and 80p in 2002. Band D occupiers will have seen their bills rise by an average £142 over the period.
Birmingham Social Services, the largest in the country, wants the Government to investigate the impact on local authority provision.
Sue Anderson, cabinet member for social care and health, said the arrival of foreign migrants was bound to place a burden on local government infrastructure.
Coun Anderson (Lib Dem Sheldon) added: "It is fine for people to come here as long as we have the money and the capacity to provide the support services that families need.
That is housing, schools, GP services, dentists and many other services that people do need to be able to lead successful lives.
"The question is whether we have enough capacity and finance within our infrastructure in order to provide them with quality of life."
However, Birmingham City Council officials were last night attempting to play down any involvement in attempting to extract additional cash from the Government.
Senior councillors and council officers were unavailable for interview.
However, a spokesman said: "Birmingham City Council has not signed up to any campaign for an alteration of systems for counting migration and immigration.
"A member of staff did attend a meeting last week at which the issue was discussed."