SINGAPORE - A nurse punched his sister's former boyfriend in the face during a family dispute, leaving him with multiple facial fractures.

Muhammad Hadi Nuri, 28, landed the blow on 24-year-old Muhammad Ridwan Omar because he felt he had made an "arrogant face" at his mother.

Hadi was sentenced to six weeks' jail on Wednesday (Aug 1) after pleading guilty to an assault charge.

Deputy Public Prosecutor Gail Wong told the court that Mr Ridwan and Hadi's sister, Ms Nur Nadia Nuri, 26, were in a relationship in 2015 but they later broke up as their family members did not approve of them being together.

Mr Ridwan and Ms Nur bumped into each other during a Hari Raya bazaar in Haig Road on June 4 last year.

Hadi's family members spotted them chatting and Ms Nur later texted Mr Ridwan to ask him to meet her at a nearby void deck.

There, Ms Nur's 50-year-old mother asked Mr Ridwan to explain his relationship status with her daughter.

DPP Wong said: "During the talk, the accused suddenly came over and punched the victim's face without provocation... and also grabbed his neck.

"A scuffle ensued between both parties before they were separated by the witnesses and passers-by. The accused later revealed that he had punched the victim as he felt angry that the victim was giving an 'arrogant face' to his mother."

Mr Ridwan was diagnosed with multiple facial fractures at Changi General Hospital.

He was given 17 days of hospitalisation leave.

The court heard that Hadi later gave him $6,290 as compensation for his medical expenses.

Hadi is now out on bail of $15,000 and he was ordered to surrender himself at the State Courts on Aug 6 to begin his sentence.

For assault, he could have been jailed for up to two years and fined up to $5,000.