The Prime Minister described the numbers so far this year as "reasonable".
As for the possible Tory rebellion on the Coalition's Immigration Bill on Thursday, Mr Cameron made clear he shared the frustrations of his colleagues but appealed for them to allow the legislation to proceed uninhibited.
"We extended the transitional controls from five years to seven years. Those seven years are now up. We are not allowed under the current rules to extend them further," he explained.
"We paused the Bill over Christmas and now we can see, at the start of the year, so far there looks to be a reasonable level of migration. I hope we can make progress with the Bill because it does so many other good things," said Mr Cameron.
He pointed to migrants paying for NHS treatment, having no right to council housing and a foreign worker having to appeal deportation from their own country of origin.
The PM admitted he was not basing his view of 2014 migrant numbers on official statistics but on newspaper reports. He told a business audience: "There aren't any official statistics. I haven't been looking at any unofficial statistics. But just from what I read and see and hear, as you have, these numbers look... reasonable."
Some 70 Conservative backbenchers have signed an amendment to the Bill, calling on the Government to reinstate restrictions on migrants from Bulgaria and Romania working in Britain until the end of 2018.
Tory MP Nigel Mills, who is spearheading the drive, said he did not wish to "crash" the legislation but insisted it must contain extra restrictions.
"We do need to set out very clearly that we have real concerns about the level of EU immigration," he said.