SINGAPORE - A 46-year-old man suffered head injuries after falling almost 2m from a walkway at Upper Circular Road. He thought he was leaning into a railing, without realising the top part of the barrier was missing.

The unnamed victim had lunch with his colleagues at the Riverwalk Tandoor restaurant when the accident happened.

The group of 16 to 20 people were taking a group photo after their meal, said restaurant manager John Calingasan, 28.

Mr Calingasan was preparing to take their photo when he heard a loud crack. One of the diners had landed near the entrance of an underpass about 1.8m below.

"He didn't notice that the barrier's top rail was missing... then he dropped from there," he told The Straits Times.

He said the top part of the railing had been missing for a few months.

There was blood flowing from the side of the man's head, he recounted.

"He didn't move for almost two minutes, then I saw blood and he started to shake."

Mr Calingasan called for an ambulance while restaurant staff and the man's friends spoke to him to comfort him.

The ambulance came in five to 10 minutes, and the man was taken to Singapore General Hospital.

The Singapore Civil Defence Force (SCDF) said that they received a call about the incident at 1.51pm.

The man suffered head injuries but was conscious when he was taken to hospital, SCDF said.

Construction workers came to fix the broken railing on Monday, Mr Calingasan said.