Former National University of Singapore law professor Tey Tsun Hang has started his five-month prison sentence for corruption.

The 42-year-old former lecturer appeared in court on Wednesday afternoon to surrender to a district court.

Tey arrived at the Subordinate Courts at about 3pm with his head shaved. When asked by reporters why he shaved his head, he said with his lips trembling: "I thought I should do it by myself, instead of (having it shaved) by the system."

Just before he was taken to the lock-up, Tey unfolded a piece of paper from his shirt and read aloud in Japanese to two former colleagues in court. He said the note was "on behalf of my beloved wife and daughter".

The Straits Times understands that he still intends to continue with his appeal.

A district court had found Tey guilty of six counts of corruptly obtaining gifts and sex from former student Darinne Ko in May this year.