Parents who have bought magnetic block sets and buckyballs for their children should take care as the magnets could be swallowed and cause serious harm.

In a statement yesterday, Enterprise Singapore, the regulatory agency for product safety of consumer goods, said similar toys like those from online stores such as Shopee, Qoo10, Ezbuy and Lazada had caused serious incidents in other countries, where children needed surgery after swallowing them.

It said the 10 toy samples it tested last month were all unsafe, having high-powered magnets that could cause intestinal injuries if swallowed, plastic packaging that was not up to par, and lacking warning signs in English of small parts that could pose hazards.

The suppliers of magnetic building blocks such as Keaihao, Tensoger, Tong Yuan, Zhond Toy and Mag-Fun, and of buckyballs have been told to stop selling them. Parents who bought them for their children should remove them immediately, said Enterprise Singapore.

In China, a 14-month-old boy swallowed 21 magnetic balls and had emergency surgery after the balls formed a ring in his stomach.

"The tiny magnets can attract one another through the intestines, and potentially result in injuries such as perforation, scarring or infection," Enterprise Singapore said.

In addition, the agency also warned that plastic bags used to package the toys could cause suffocation.

Some products were also inappropriately marketed to users who were too young. For instance, buckyballs intended for use by adults as a stress-relieving tool were advertised as toys for children.

Enterprise Singapore advised parents to buy toys only from reputable brands and sellers.