International students coming to London contribute £2.3bn towards the economy, according to a report.
They say migration targets should be reclassified and students should have visitor status and be able to work after graduating.
The Home office says all immigrants in the UK affect communities, housing and public services and should be included in net migration figures.
But the report argues international students are made to feel "unwelcome".
The research was commissioned by London First, an organisation representing businesses in London and the accountancy firm PwC.
Students who responded to the study came from about 70 countries and attended 10 of the 39 higher education institutions in London.
As well as contributing to the economy, the study says, international students "support nearly 70,000 jobs" because of the money they spend in the city.
But, a vast majority of the students said it was difficult for them to secure work after they had finished their courses because of the complex immigration system.
Jo Valentine, chief executive of London First said: "International students are made to feel unwelcome because of the anti-immigration rhetoric," and because they are included in the government's net migration targets.
"Students' expenditure here is a modern-day export: they pay substantial fees and contribute significantly to consumer spending."
Calculations by the research team show, they say, that international students do not burden public services.
Their figures show that while international students contribute a "total of £2.8bn" through the spending they bring to the country, they consume £540m in public spending, including the NHS.
Julia Onslow-Cole at PwC said: "While politicians recognise the importance of international students, there has been considerable debate over their economic value.
"This is the first study to quantify the benefits of student migration.
"We need more hard data like this to inform immigration policies and targets."
Immigration minister James Brokenshire said: "The government will pursue further reforms to tackle abuse while continuing to attract the brightest and the best to our world-class universities."
"The latest figures show this strategy is working - university applications from overseas students are up by 18% since 2010."