Universities are condemning government plans to abolish the right of appeal of students refused visas for the UK.
Students are important for UK economy, universities say
In an open letter, all 120 university leaders in Universities UK say the move in the Immigration, Asylum and Nationality Bill is "wholly unjust".
They say immigration decisions "are subjective and often wrong" and the UK risks losing its competitive position in higher education.
The government says it welcomes students and most satisfy the rules.
The Universities UK president, Ivor Crewe, said: "The government's own figures show that one in four visa appeals are successful - proof that this is a deeply-flawed system."
The bill is due to receive its second reading in the House of Commons on Tuesday.
As well as writing to the Financial Times, Universities UK is briefing MPs beforehand.
Representatives of the National Union of Students are also attending.
Its international students officer, Benson Osawe, said: "International students make a huge contribution to the UK not just to the economy, but to the education, cultural and social environment.
"This is the latest in a string of attacks on international students, who have seen initial and extension visa charges increase dramatically over the past few months.
"Discriminatory policies such as these will deter international students from this country at a time when the UK needs to position itself as an optimum study location."
International students provide important funds for universities.
There is no cap on fees to students from outside the European Union, who typically pay far more than home students.
Universities UK said it was committed to supporting the government's attempts to prevent abuse of the immigration system, but abolishing the right of appeal would send the wrong message.
Speaking on BBC Radio 4's Today programme, Immigration Minister Tony McNulty said that the warnings from the universities was an "over-reaction".
"We need to streamline the decision-making process. We want to get to the stage where the appeal process goes and the decision-making process is far, far more robust than it is at the moment," said Mr McNulty.
A Home Office spokesman said the UK was committed to encouraging migrants with the skills the country needed, and welcomed students' cultural and financial contributions.
Removing the right of appeal had been a manifesto commitment. There was no reason to believe it would have a significant impact on prospective students.
"The majority of students are granted entry clearance because they meet all the requirements of the immigration rules.
"Removing the right of appeal in cases where the rules are not met will free up resources to enable other appeals - such as more important asylum, family and human rights cases - to be resolved more quickly."