The recent spate of cyber hacking incidences should not be taken lightly, as it "causes inconvenience to others and... sometimes serious disruptions to services which are important to many people in the country," said Deputy Prime Minister Teo Chee Hean on Sunday.

He was speaking to the media on the sidelines of a parenthood event at the Pasir Ris Elias Community Club.

On Wednesday, the websites of 13 schools, including Raffles Girls' School (Secondary), St Andrew's Junior College and Henderson Secondary, were hacked by a person or group who signed off as "Jack Riderr". The Singapore Art Museum also admitted on the same day that the names, e-mail addresses and, in some instances, nationalities of 4,000 individuals on its online mailing list were illegally published on a New Zealand-based website on Nov 5. The authorities said they were still investigating if the museum's website had been hacked.

Mr Teo, who is also Minister for Home Affairs and Coordinating Minister for National Security, added: "In many cases, what they do is illegal, and we will take action against them if we can find them, and arrest them."