Curves are out at several Islamic universities in Indonesia, which have shut the door on female students wearing tight jeans and body-hugging shirts.

The State Institute of Islamic Studies in Indonesia's second-largest city Surabaya said the dress code banning tight attire was introduced this week after complaints.

"We will have staff watching at our entrances and students who don't wear proper clothes can't enter the campus," deputy rector Hamid Syarif told Reuters on Friday.

The rules did not apply to male students, who were instead discouraged from wearing T-shirts and torn jeans, Syarif said.

Jakarta's Islamic State University has introduced the fashion code because it wants to stop students blending traditional and modern styles in the world's most populous Muslim nation.

Indonesians have long followed a moderate version of Islam, although an emphasis on Muslim practices and identity with Islamic traditions has gathered pace in recent years.

"Even if the students wear a jilbab (headscarf) they also wear tight clothes that show off their body shape and this is not how it is supposed to be," said Nurul Jamal, head of the university's student affairs division.

He said male students were allowed to wear jeans but forbidden to grow hair past their shoulders.