There are no reliable estimates over how many Romanians and Bulgarians will come to Britain when access restrictions are lifted at the end of this year, a Cabinet minister has admitted.
Communities Secretary Eric Pickles said any influx from the European Union states would "cause problems" with services such as housing. The highest numbers were likely to arrive in London boroughs that already have significant populations from the countries.
However, he insisted it was not "reasonable" to assume that 300,000 would move to the UK - the figure suggested by some Tories based on migration levels after Poland, the Czech Republic, Latvia and Lithuania acceded.
The comments came after the coalition confirmed it would not seek to extend temporary curbs on 29 million Romanian and Bulgarian nationals' right to live and work in Britain, which are due to expire in December.
Speaking on the BBC's Sunday Politics programme, Mr Pickles said there had not been any discussions with the Home Office about potential numbers. He suggested his own department had come up with figures - but refused to say what they were.
"The truth is I don't think anybody entirely knows the number that are going to come from Bulgaria or from Romania," he said.
"I've seen figures, I wasn't confident with those figures. I've asked for a further explanation and when I've got that explanation and when I feel confident about the figures then I'll talk about the figures."
Mr Pickles went on: "Given that we've got a housing shortage, any influx from Romania and Bulgaria is going to cause problems and it's going to cause problems not just in terms of the housing market, but also on social housing markets.
"But one of the reasons why I'm not prepared to start a scare story going is that I think we need to be reasonably confident about the figures."
Labour indicated last year that it supported extending restrictions on migrants from the two countries working in the UK.
https://www.gov.uk/government/organisations/department-for-communities-and-local-government(Department for Communities and Local Government)