Eighty students at Prairiewood High School in Sydney's south-west have been suspended for illegally accessing a teacher's internet account.

A statement from the New South Wales Education Minister says the students logged into the teacher's departmental computer account to access sites like Facebook and Twitter, which students are not allowed to view from their own accounts.

The statement says no illegal, pornographic or student record material was accessed, but police were called.

The 80 students have been suspended for four days.

They will have to attend a meeting where they will be warned by police about the criminality of accessing computer material without authorisation.

All Prairiewood High School teachers have now changed their computer passwords and have been reminded about following appropriate IT security measures.