The possibility of a tax on privately held wealth arose yesterday in off-the-cuff remarks by Finance Minister Heng Swee Keat.

Mr Heng, who was attending the official opening of Nanyang Technological University's Wealth Management Institute at one-north, recalled a question put at The Straits Times Global Forum on Tuesday, where he was asked why government revenue has to be raised instead of touching the nation's reserves. He told the audience yesterday before his official speech that he had made the case at the forum that the reserves were used in times of need, such as during the global financial crisis.

This policy, he added, led to the continued stability of the Singapore dollar and sustained economic growth.

Mr Heng joked: "I don't know if the person who asked the question was someone from the wealth management industry who thought that I was thinking of taxing wealth and trying to divert me from doing that. Unfortunately, he had the opposite effect. I had a few people come up to me after that and said: 'Minister Heng, I'm convinced you don't touch sovereign wealth, but what about private wealth?'"

Mr Heng did not elaborate any further on tax policy.

Prime Minister Lee Hsien Loong recently said it is "not a matter of whether, but a matter of when" taxes would have to be raised, sparking speculation that the goods and services tax (GST) was a top contender for a hike.