A salesman was jailed on Wednesday for a month for punching the 20-year-old boyfriend of an 18-year-old student he knew.

Leang Shi Ming, 24, had sent her a text message at 3am on June 16 last year asking her if she was free to talk.

Mr Edwin Poo Wei Lun, who was sleeping over at the student's Punggol flat, replied the text and told Leang to leave her alone as she was very young.

After a flurry of text messages between the two men, they met at the void deck at 4.45am where Leang punched Mr Poo, causing fractures near his eyes.