A man who held his girlfriend's two-year-old son hostage and engaged in a 17-hour stand-off with police was convicted yesterday of kidnapping the child, as well as three other charges.

Muhammad Iskandah Suhaimi, 40, admitted to taking the toddler from his mother without her consent, having a knuckleduster, and possessing and taking crystal methamphetamine or Ice the day after he took the child.

Neither his 33-year-old girlfriend nor her son can be named due to a gag order.

At about 4pm on Sept 27 last year, Iskandah - who had been living in the rental flat for about a year with the victim and his mother - told his girlfriend to buy cigarettes for him.

When she stepped out of the flat with her son, he suddenly grabbed the boy and locked the main gate, with the victim inside.

He ignored his girlfriend's requests to let the victim go. She was afraid as she had not been apart from her son before and usually did not leave him alone with Iskandah.

Iskandah rejected her pleas to release the boy and he challenged her to call the police. She then went to get her mother's help and returned to the flat with her.

Deputy Public Prosecutor Stephanie Koh said Iskandah still refused to let the victim go and said he would only do so if his girlfriend agreed to enter the flat in exchange for the victim. The girlfriend and her mother both did not agree as Iskandah had a history of violence towards his girlfriend.

Police arrived at about 7pm, 15 minutes after they were alerted.

Iskandah's girlfriend told the police that he had taken Ice earlier that day.

She also said they were having relationship problems, that he had hit her before, and was known to carry a knuckleduster with him.

DPP Koh said Iskandah continued to demand that his girlfriend go into the house in exchange for the child's release.

Iskandah was aggressive, uncooperative, impatient and highly agitated at various points in his dealings with the police, the court heard.

During the stand-off, he was seen taking drugs in the flat.

At around noon - the day after the stand-off started - a team from the Special Operations Command forced its way into the flat by breaking a the window and removing the front gate when Iskandah went to the toilet. The victim was rescued and Iskandah was arrested.

He had thought that his girlfriend would call the police and report him for taking drugs if he allowed her to take the child with her.

DPP Koh said the stand-off lasted about 17 hours - from about 6.40pm on Sept 27 to about noon the next day.

District Judge Carol Ling adjourned the case to Feb 26 for sentencing.