SINGAPORE - A man was injured when a glass door at the National Gallery Singapore broke on Tuesday (Dec 1) afternoon, just one week after the museum opened to the public.

The door led to a rooftop garden, said Ms Denise Chong, who was visiting the gallery.

She was on the fourth floor when she heard "a popping sound" and some commotion. She went up one floor to check. A large pile of glass on the floor could be seen in photos taken by Ms Chong.

A man was injured, and was given first aid. There appeared to be blood on his hand, said Ms Chong, 41.

A number of people gathered around when the accident happened before 5pm, she added.

A spokesman for the National Gallery confirmed that a visitor suffered minor abrasion on his right hand when the glass door on level 5 broke at about 4.50pm. The visitor was immediately given first aid by the gallery's staff.

Investigations are ongoing to determine the cause of the incident. In the meantime, the affected area will be cordoned off for repair works "until further notice", said the spokesman.

The Ng Teng Fong roof garden gallery and restaurant Smoke and Mirrors remain accessible to the public.

"We will conduct thorough safety assessments again once repair works are complete," the spokesman said.

The spokesman added that the National Gallery uses tempered glass for all its glass, which are made in Singapore, China and Malaysia. The one that shattered was made in Singapore.

The 64,000 sq m National Gallery is housed in the City Hall and former Supreme Court. The $532 million project took 10 years to complete.

It is Singapore's first large-scale building dedicated to Singaporean and South-east Asian art.