The number of Eastern European workers registered for jobs in the UK has reached half a million, figures show.
There were 59,365 arrivals between June and September
Government data shows 510,000 workers have signed up since eight countries joined the European Union in May 2004.
Including the self-employed, some 600,000 Eastern European workers are thought to have spent at least some time in the UK over the past two years.
The figures count those applying for jobs, not the number of migrants who have permanently settled in the UK.
Around 59,000 people signed up for the Worker Registration Scheme between June and September 2006, the Accession Monitoring Report revealed.
It compares to 61,000 for the same period last year.
The scheme was put in place as a transitional measure to regulate the access of workers from the 'Accession 8' or 'A8' countries to the labour market and restrict their access to benefits.
Of the 510,000 total, Poles made up 63% of the total - more than 300,000 - followed by Lithuanians at 11% and Slovaks were third at 10% of the total.
The Anglia region had the greatest number of registered workers - 73,000 or 15% of the total.
It was followed by London and the Midlands with 14% and 12% respectively.
Immigration Minister Liam Byrne said: "The latest Worker Registration Scheme figures show that migrant workers from the accession states are benefiting the UK by filling skills and labour gaps that cannot be met from the UK-born population.
"However, we need to make progress on our immigration reforms and understand the transitional impacts from the last round of accession in 2004 before we take the next step."
He said for this reason it was decided to "gradually open up" the UK's labour market to workers from Bulgaria and Romania after they join the EU in January.