The Tories questioned the figures used by Gordon Brown in his podcast
The Conservatives have accused Gordon Brown of "dishonesty" over immigration figures used in a Number 10 podcast.
Mr Brown said net migration into the UK fell from 237,000 in 2007 to 163,000 in 2008 and provisionally 147,000 in 2009.
The Tories said the figure for 2009 was only for the year up to June, and excluded asylum seekers and people overstaying their original visas.
A Downing Street spokesman said the prime minister had made it clear he was using a provisional figure for 2009.
The Conservatives' interpretation of the figures has been confirmed by the Office for National Statistics.
Shadow Home Secretary Chris Grayling called it "another extraordinary example of Gordon Brown's dishonesty".
Mr Brown said in the podcast: "Our new points system is radically changing the way we are dealing with immigration from outside the European Union.
"The essence of it is to refuse entry to people who cannot contribute to the economy in the way we need - and to clearly delineate those skills that we cannot immediately generate in our own country."
In response, Tory immigration spokesman Damian Green said: "If it wasn't such a serious issue you would have to laugh. After 13 years of an open door immigration policy Gordon Brown now admits we need controls.
"His government has not offered any serious controls, so Britain will have to wait for a Conservative government to introduce an annual limit on work permits, effective controls on student visa abuse, restrictions on those coming here to get married, and a Border Police Force.
"Then we will get immigration under control, to the benefit of everyone including new and recent arrivals."