Student visas have become the "back door to Britain" and the government must tighten the noose on the student system, a campaign group has warned.
Removing international students from official migration statistics will destroy public confidence in the government's immigration policy, Migration Watch UK claim.
The concerns come after a letter was penned by almost 70 chancellors, governors and university presidents warning crackdowns could lead to foreign students going elsewhere, costing the British economy billions.
Removing overseas students from migration figures, as suggested by the chancellors, would undermine the credibility of the entire system, the Migration UK said.
The pressure group added no other major country does so for their net migration calculations.
Sir Andrew Green, the group's chairman, also called for interviews to establish whether overseas students are genuine and that they intend to return home at the end of their course to be brought back.
"Foreign students are valuable but the present system is far too easily abused," he said.
"Sadly, the student route has become the back door to Britain and it is wide open.
"Unlike our main competitors, we do not interview students before they come to confirm that they are genuine and there are no checks on their departure."
He went on: "We cannot have a massive inflow of a quarter of a million students a year without their contributing heavily to immigration.
"Taking them out of the statistics would achieve nothing. The government must thoroughly tighten up the student system or any attempt to reduce the current mass immigration will be blown seriously off course."
A report published by the group added that removing overseas students from the migration figures would be "distorting reality".
"If the public are to have faith in the immigration statistics, excluding a high proportion of those who enter (and stay in) the UK would undermine the credibility of the entire system - especially as no other major country does so," it said.
"There is more than enough mistrust in this field without adding to it further."
Study remains the most common reason for migrants coming to the UK and the row comes after university chancellors wrote to David Cameron last month, encouraging him to do more to boost the number of overseas students even further.
Britain attracts around one in 10 students who study outside their home country, generating around £8 billion a year, "with forecasts suggesting that export earnings from this activity could more than double by 2025", they told the Prime Minister.
"We therefore ask you to consider how your government can do more to support our universities in their international activities.
"In particular we request that international university students be removed from the net migration statistics for policy purposes, bringing us into line with our major competitors.
"We believe that this would help government by creating a clear differentiation between temporary and permanent migration, help universities whose international character is essential to their future success, and help the UK by contributing to economic growth."
Nicola Dandridge, chief executive of Universities UK, said that while the report made important points, it was "wrong in calling for international students to be counted within the UK's migration figures".
"The chancellors were calling for the government to remove international students from net migration figures in order to make a clear distinction between temporary and permanent migrants for the UK's own internal policy purposes," she said.
"This would actually increase public confidence in the immigration system.
"No one is suggesting that international students should not be counted in the immigration system."
She went on: "International students come to the UK for a period, then they go home.
"The small numbers who wish to stay after their studies must then apply for another visa. If that application is unsuccessful, they must return home.
"Universities UK is saying that we must take genuine international students, who come and then go, out of the definition of net migration equation."
Dandridge added: "We must be careful that legitimate concerns about immigration do not end up damaging our reputation for being a welcoming and world-class place to study."
Immigration Minister Damian Green said: "We are glad that Migration Watch agree with us that overseas students should remain part of the net migration figures and that action needs to be taken to prevent abuse of student visas.
"That is why we are introducing a raft of changes to the student visa route.
"We have also recently piloted interviewing students as part of the visa application process and have already committed to reintroducing full exit checks by March 2015."