Downing Street has insisted that the Prime Minister's flagship target of getting immigration below 100,000 a year has not changed, after Home Secretary Theresa May appeared to downgrade it from a promise to a "comment".
Mr Cameron told the Confederation of British Industry that he will continue to push for reforms of EU immigration rules, despite the belief of many business leaders that migrant labour is good for the economy.
Experts believe that David Cameron has little chance of hitting the 100,000 target by next May, after official figures showed that 243,000 more migrants came to the UK than left in the year to March - up from 175,000 the previous year.
The figure was identified as a "goal" in the Conservative manifesto for the 2010 election, and Mr Cameron repeated it as Prime Minister in a speech in 2011, saying he would get immigration to levels the country could manage, and adding: " No ifs. No buts. That's a promise we made to the British people. And it's a promise we are keeping."
In an interview with BBC Radio 4's Today programme, Mrs May appeared to water down the commitment, saying: "When we made that, er, comment... we said we would be aiming to bring the net migration down to the tens of thousands and we wanted to do that within this parliament. Yes, we were very clear that's what we wanted to do."
Challenged at a regular Westminster media briefing over whether the promise was being downgraded, Mr Cameron's official spokesman said: "There is no change. That remains the objective towards which the Prime Minister and others are working.
"It has always been the objective to cut it tens of thousands by the end of this Parliament. There is no change."
But the spokesman dodged several opportunities to confirm that the PM's target had the status of a "promise". Asked whether Mr Cameron regarded it as a promise, the spokesman said: "His approach, his view, hasn't changed at all. It remains exactly as he has described it.
"There is absolutely no change in the objective we are working towards."
In a speech to a CBI conference in London, Mr Cameron restated his determination to impose "proper " controls on immigration - including reforms to movement from within the European Union.
Mr Cameron said that tighter immigration controls must be matched by reforms to the UK's welfare and education systems to enable British workers to fill the jobs currently done by foreigners.
"We need to have proper immigration control. We need to do more, both outside the European Union and, frankly, inside the European Union," said the Prime Minister.
"But the flipside of the coin on immigration is a welfare system that rewards work and an education system that turns out people with the skills necessary to do the jobs that we are creating in our country today.
"No immigration policy will succeed unless it's accompanied by that welfare and that education reform as well."
His comments came after a string of EU leaders raised concern about indications that Mr Cameron wants to reform the fundamental right to free movement for workers from throughout the 28-nation bloc.
Coalition Government successes in bringing down immigration from outside Europe over the past four years have been outweighed by a surge in arrivals from other EU states.
German chancellor Angela Merkel has made clear she regards the principle of free movement of labour within the European Union as non-negotiable and is reported to have warned the Prime Minister that his drive is pushing Britain towards "a point of no return" on the road to exit from Europe.
Similar concerns were aired by northern European leaders at a summit in Finland last week, where Mr Cameron acknowledged there were "different perspectives" but insisted there was "common ground" on the need to reform.
Mrs May told BBC Radio 4's Today: "What I have seen over the last few years - because I have been talking about freedom of movement for some time in Europe - is a growing recognition from other countries that actually there are issues.
"It is possible to get change in this area. There is a growing concern across the European Union of the way in which free movement is being used. We are seeing it being abused, possibly by criminal gangs that are trafficking human beings, we are seeing it being abused through sham marriages."
Asked about other member states' concerns, she said: "They have been clear about the principle of freedom of movement. I wouldn't expect them to be anything otherwise.
"We are going to be going into a negotiation that would lead to a referendum in 2017 ... you wouldn't expect everybody to be giving everything away to us at this stage."
Shadow home secretary Yvette Cooper said: "The Prime Minister promised 'no ifs, no buts', his Government would get net migration down to the 'tens of thousands'. He said it was 'a promise to the British people' - part of the contract he put on leaflets to voters across the country.
"But today, the Home Secretary described the net migration target as a 'comment', rather than a promise. Did she think we'd just forget what the Prime Minister had said? Does she think voters won't remember the Tory leaflets pushed through their letterboxes with this immigration pledge on?
"It's time Theresa May stopped ducking and diving and took some responsibility for the fact that her net migration target is in tatters, so we can start having a serious conversation about the future of our immigration system and the reforms that are needed."