The National Tertiary Education Union is concerned about a big fall in the number of international students wanting to study in Australia.

Visa applications for higher education fell by 11 per cent last year compared with the previous year.

The union says there are many reasons for the fall, including attacks on students and a crackdown on disreputable providers.

The union's Victorian secretary Matthew McGowan says the fall gives a clear message to both sides of federal politics.

"Both major parties need to re-think the way in which they engage in debates around immigration and people coming to Australia seeking asylum," he said.

"I think that these things are sending strong messages to the communities in other countries, and it is not helping the higher education sector."