An IT company manager who carried out a campaign of abuse against an intern was yesterday sentenced to a 10-day short detention order (SDO).

The community sentence is served in prison, but carries no criminal record.

A judge said that Lee Yew Nam, 45, the manager of Encore eServices, had used 32-year-old Calvin Chan Meng Hock like a "punching bag" - slapping and hitting him during a string of violent outbursts when he felt his work was not up to standard.

He was caught when another intern took a 17-second video of him hitting Mr Chan, and posted it online.

Lee was convicted of four charges of causing hurt to Mr Chan at his Jurong Town Hall Road office between January and May 2013.

Two other charges of causing hurt and using abusive words were considered in sentencing.

The court was told that in January 2013, Lee slapped Mr Chan once in the face for failing to neatly arrange several software files in a computer.

The following month, he punched Mr Chan in the face several times, then pushed him off his chair, as he believed the intern had failed to correctly answer a customer's request.

On May 14, 2013, Lee grabbed Mr Chan's chin and forcefully pulled it back after finding out he had forgotten to delete files from a database.

The abuse that was caught on camera took place the next day, after Lee went through a conversation log between Mr Chan and a customer.

Lee felt Mr Chan had failed to perform his work well, and questioned him. When Mr Chan gave him an explanation deemed unsatisfactory, he became increasingly agitated and started to shout at the younger man. Lee then punched him in the head before slapping him three times.

In passing sentence, District Judge Lim Tse Haw said the 10-day SDO imposed would be sufficient to deter like-minded employers from laying their hands on their employees.

"A strong message must be conveyed to all employers that such brutish behaviour has no place in our civilised society," he said. "It must be made clear to all employers that an employee, no matter how low his position in the company is, is an important member of the company and not a punching bag, not even for stressed-out employers."

The judge considered Lee's clean record, his plea of guilt, albeit at a late stage on the first day of his trial, his $5,000 voluntary compensation and the fact that he was suffering from a depressive disorder.

However, he said he could not ignore the fact that what Lee had done was a serious matter. "As a responsible employer, he has a duty to have regard for the well-being and welfare of his employees.

"Instead, he subjected the victim to physical hurt and verbal abuse on numerous occasions, once in 2010/2011, and five other occasions from January to May of 2013."

Lee's lawyer Diana Ngiam successfully applied for her client to start his sentence on April 8. The maximum penalty for causing hurt is two years in jail and a $5,000 fine.