Higher wages have drawn many young Poles to London
The influx of Eastern and Central European migrants to older EU states has not destabilised their labour markets, the European Commission says.
Fears of immigrants like the archetypal "Polish plumber" taking local jobs have been raised in several countries.
A report by the commission says the proportion of Eastern Europeans in old EU member states rose from 0.2% of the population in 2003 to 0.5% by 2008.
But they helped growth by filling jobs, and did not drive down wages, it says.
The number of immigrants from Eastern Europe grew substantially after EU enlargement in 2004.
The "Polish plumber", a symbol of cheap migrant labour, became a catchphrase of the French "No" camp in the run-up to the 2005 referendum on the EU constitution - which French voters rejected.
"There is still much more migration from non-EU nationals than new to old member states," the commission says in the report released on Tuesday.
More non-EU workers
According to the EU statistics agency Eurostat, in 2006 the number of EU citizens who moved to another EU state was 1.2 million, while the number of non-EU immigrants was 1.8 million.
The 2006 figures for the UK's largest immigrant groups - not including immigrants from the Republic of Ireland - are: Poland - 13%, India - 13% and China - 6%.
Eurostat found that in 2006, the largest number of foreign immigrants was recorded in Spain (803,000), followed by Germany (558,500) and the UK (451,700). These three countries received 60% of all foreign immigrants to the EU.
When eight former communist countries in Eastern Europe joined the EU in 2004 three member states lifted labour market restrictions: Ireland, Sweden and the UK. The others kept restrictions in place, to varying degrees.
In 2007, when Bulgaria and Romania joined, 15 of the 25 EU member states - including the UK - kept their work permit systems, limiting jobs for Bulgarian and Romanian workers.
Spain and Italy have been the main destination for Romanians.
I call on member states to consider whether the temporary restrictions on free movement are still needed, given the evidence presented in our report
EU Commissioner for Employment
The commission says the economic slowdown has already led to a substantial reduction in immigration to some member states, along with an increase in return migration.
"This is a sign that free labour mobility is self-regulatory by nature and provides a much-needed flexibility in both directions," the report says.
It sees the free movement of labour not only as a core EU value but also as a means to reduce black market activity.
In April this year research by the UK's Institute for Public Policy Research suggested up to one million immigrants from Eastern and Central Europe had arrived in the UK since 2004. But it said about half of these migrants had now returned home.
According to the Eurostat figures for 2006, the highest rates of foreign immigration per head of population were in Luxembourg (28.8 immigrants per 1,000 inhabitants), Ireland (19.6), Cyprus (18.7), Spain (18.1) and Austria (10.3). The EU average was 6.2 per 1,000.
Some member states had a high concentration of immigrants from a particular country: Romania (56% from Moldova), the Czech Republic (46% from Ukraine), Slovenia (43% from Bosnia-Hercegovina) and Greece (42% from Albania).
The largest foreign immigrant groups across the EU were citizens of Poland (about 290,000), Romania (about 230,000) and Morocco (about 140,000).
Eurostat cautions that the figures are based on national statistics which are "not fully comparable and must be interpreted with care".