Home Secretary Theresa May has confirmed that Bulgarians and Romanians will in December 2013 have unrestricted right to live and work in the UK.
In 2005 the government imposed temporary curbs to protect the British labour market. The curbs will expire on that date.
While the Labour Party is ready to support any moves to extend the ban, Mrs. May told the BBC's Andrew Marr show that was not possible under EU law.
"There are no further transitional controls we can put on. The transitional controls end in December 2013," Mrs. May said.
She however said she was hoping to limit the impact on the UK economy.
The government was looking instead at limiting access to benefits and the NHS to reduce the "pull factors" that encouraged migrants to come to the UK, she added.
There is no official estimate of how many Romanian and Bulgarian citizens will take advantage of their new freedoms when controls are lifted.
BBC reports that some experts predict a large number of immigrants from Eastern Europe, which Labour has warned could put pressure on British jobs and wages.
There is evidence, says the government's migration advisory committee, that Bulgarians would move to Britain because of its stronger economy. The committee also holds that it is "plausible" Romanians would come for the same reasons.