A father who whipped his son over the legs with a coat hanger, saying he was disciplined that way as a child, will face punishment in court next month after he pleaded guilty to assaulting the boy.

Szu Sheng Lo, 41, admitted hitting the 12-year-old boy in Canning Vale on December 23 when he appeared in the Armadale Magistrate’s Court today.

The court was told the child had behavioural problems and Lo said he used the coat hanger to discipline him because he faced a similar penalty when he was a young boy.

“I did that because that had been done to me from a young age, from my primary school teacher,” he said.

“So it worked on me when I was young.”

Magistrate Steven Malley said Lo effectively used a “weapon” to punish his son, saying “if you whip someone on the leg with a coat hanger, there are not too many defences to that”.

Mr Malley said for people of “my generation”, corporal punishment was “not unusual”, but said “it’s a new generation” and the practice was no longer acceptable.

“Parents are entitled to use discipline, and that’s reasonable discipline,” he said.

“Once you use an object ... then you’re out of the game.”

After pleading guilty to common assault in circumstances of aggravation, Lo, who does not have a criminal record, requested a spent conviction.

But Mr Malley said it was a “reasonably serious matter” and that he would need more information, such as references, before he made a decision.

Outside court, Lo said he regretted his actions.

“They have disabilities,” he said. “We have a lot of stress difficulties to take care of them.”

Lo will return to court on January 18 for sentencing.