An undergraduate was charged on Wednesday with molesting a 19-year-old girl at a hostel toilet of Nanyang Technological University last September.

Nguyen Minh Dung, 19, a Vietnamese national, is alleged to have put his hand under the girl's skirt and touched her buttocks three times, saying that she had a "nice butt''.

The alleged offence took place in a male toilet of the hostel at about 4.30pm on Sept 14 last year.

Bail of $6,000 was offered. He will appear in court again on Feb 13. If convicted of outrage of modesty, he could be jailed for up to two years, fined, caned or receive a combination of the sentences.