A man who shoved an elderly woman on a bus was ordered on Friday to undergo two years of mandatory treatment for his psychiatric conditions.

Ong Kok Hao, 25, had pleaded guilty last month to hurting Madam Hwang Li Lian, 76, by pushing her in her back and causing her to fall down the steps of bus service number 167 on June 5 last year. A video clip of him pushing the woman went viral and the incident sparked an online uproar.

Ong had been diagnosed with clinical depression since 2009, and also suffers from obsessive compulsive disorder and Asperger's syndrome since primary school. Asperger's syndrome is a form of autism that makes it difficult for him to interact socially with others.

Ong's lawyer, Mr Eddie Koh, told The Straits Times that the treatment order was "a good sentence" as his client will now receive consistent treatment at the Institute of Mental Health. He added that previously Ong would go for treatment "on and off".

Court papers state that the SMRT bus was travelling along Upper Thomson Road before Thomson Plaza when Ong got into a heated quarrel with Madam Hwang and pushed her down the steps.

He was annoyed that she had pressed the bell at the last minute, causing the driver to stop the bus after the designated bus stop. She suffered bruises on her legs and body.

Ong apologised to her immediately.