NSW Education Minister Adrian Piccoli has urged the federal government to restrict the number of students allowed to go to university in fields such as teaching where there are limited employment opportunities and an oversupply of graduates.

The call comes after a Fairfax Media investigation revealed that the practice of admitting students with lower than the minimum ATAR into university courses was endemic. There are currently more than one million domestic students studying in Australian universities.

"Where there are a limited number of places, or jobs available, they should be capping places," he said. "Why are we training all of these people when the majority of them won't get jobs?"