Immigration minister Damian Green will promise today "smarter" controls on entry to the UK, as he releases research showing that tens of thousands of people admitted on student visas were still in the country five years later.
In his first major speech since the coalition Government took office, Mr Green will acknowledge that the annual cap on economic migrants from outside the EU will not be enough on its own to deliver the target of reducing net immigration to the tens of thousands.
He will promise to look at "all routes into the UK" and set new rules to ensure that only the "brightest and best" migrants enter the country to study and work.
And he will give priority to improving controls over foreign students and their dependants, more than 300,000 of whom were granted visas last year.
Mr Green will say that the points-based system introduced by Labour is still not delivering proper control of numbers of migrants coming into the country.
He will promise to look into why those entering on a temporary basis are currently finding it easy to switch to a permanent basis.
Steady pressure will be applied to every route to long-term immigration to bring down numbers, he will say.
Home Office-commissioned research has looked into all of those who came into the UK in 2004 and tracked their immigration status for the following five years. All those granted settlement in 2009 were also studied to see how they entered the country in the first place.
The largest group of visas granted in 2004 were to 186,000 students, more than one-fifth of whom - over 37,000 people - were still in the UK five years later.
And the research found that numbers of visas issued to students and their dependants had risen to 307,000 by the year to June 2010.
Internal estimates suggest only around half of the students involved were pursuing courses at degree level or above.
Mr Green will also promise to look at the routes by which people who come to the UK to work go on to obtain British citizenship.
Some 106,000 work visas were issued in 2004, and two fifths of this group - over 40,000 people - were still in the UK in 2009.
Mr Green will say: "We cannot assume that everyone coming here has skills that the UK workforce cannot offer, and we will not make Britain prosperous in the long-term by telling our own workers not to bother to learn new skills as we can bring them all in from overseas.
"We need smarter immigration controls - controls which bear down on the numbers coming and welcome those we really need here.
"We are looking at all routes and will need to set rules for each of them that give us the immigrants we need."
Mr Green stressed that he did not want to hit universities' legitimate recruitment of overseas students.
He told the BBC Radio 4 Today programme: "I don't want to interfere with the success stories of our universities."
But he said there was a need to examine closely sub-degree courses and why students remained in the UK.
"Why are they staying on? What are they staying on to do? This is part of a wider look we need to take at the immigration system."Reuse content