The deputy Prime Minister has refused to reveal official government estimates relating to the number of Romanians and Bulgarians expected to come to the UK when restrictions are lifted next year.
During his LBC Radio show this morning the leader of the Liberal Democrats said making the figures public would not help "public confidence in the immigration system", and that the figures were not "precise" and were more like "guesstimates".
Mr Clegg would not say whether the official estimate was higher or lower than 13,000 people a year.
Speaking on his weekly phone-in show Mr Clegg said the government had "estimates, but they are estimates".
He continued: "I don't think we as a government should start bandying around estimates, estimates which at the moment aren't very precise."
The government has so far refused to speculate on how many people from those countries could head to Britain in search of work when restrictions on their movement of travel within the European Union are lifted in January 2014.
According to official figures in July 2012 there were 94,000 people who were born in Romania and 47,000 people who were born in Bulgaria resident in the UK.
Ukip, which is currently surging in the polls has claimed the rule changes could lead to an influx of 350,000 to 400,000 Romanians or Bulgarians into this country, and claims it will impact on crime rates.
It has said the issue would play a key part in its strategy for European Parliament elections in 2014.
Migration Watch, an organisation which supports tighter immigration controls, has predicted 50,000 Romanians and Bulgarians will come to the UK every year when the restrictions are lifted.