[UPDATE April 21]
The boy has been reunited with his family with the help of police cameras, the police told AsiaOne.
"No injuries were reported on the boy, and no further police assistance was required," the police added.
The boy's father has since explained that his son slipped out of the house when his caretakers - his grandparents and auntie - were taking a nap, reported Shin Min Daily News today (April 21).
The boy was later found in Woodlands and his father said that he has since explained the situation to the shop owners there.
It takes a whole village to raise a child, but when the kid in question is wearing only a diaper and doesn't have his parents nearby, the authorities have to step in.
A boy was seen wandering alone in Woodlands at 9pm on Tuesday (April 19), Shin Min Daily News reported.
Zhang, the owner of a mobile phone shop near Woodlands Mart, told the Chinese evening daily that a couple first noticed the child loitering in the area.
They tried to search for the kid's parents and even followed him to a nearby supermarket, but to no avail.
The couple also asked around to see if anyone recognised the boy before approaching Zhang and showing her a picture of him sitting on a kiddy ride.
"We spoke to the boy in different languages, but he kept shaking his head and refused to answer," Zhang recounted.
He appeared to be around five or six years old, she said.
After hearing about the child, other shop owners called the police for help.
Police officers arrived at the scene shortly after the call and also attempted to identify the boy by asking around. But they were unable to get any information.
"After the police arrived, I went home and grabbed some clothes to give to the boy," Zhang said.
Other members of the public also tried to give him water and food but he rejected the offers.
"The boy had been sitting on the roadside looking exhausted and about to fall asleep," she added.
After a fruitless search, the police took the boy away.
AsiaOne has contacted the police for more information.