At least 36 people have died after a Hong Kong ferry packed with more than 120 people collided with another ferry and sank near Lamma island in one of the city's worst maritime accidents.

Low visibility hampered rescue efforts, with many passengers trapped in the flooded upturned ferry before it sank on Monday night, said survivors.

Nine people suffered serious injuries or remain in a critical condition, the government said in a statement.

The accident occurred in the waters off Lamma, an island south of Hong Kong popular with tourists and expatriates.

The passengers of the stricken boat had been on their way to watch a huge fireworks display in Hong Kong harbor when their boat collided with another ferry, filling with water and quickly sinking, fire service officials said.

At least 124 passengers and crew were on the boat, belonging to the Hong Kong Electric Company, a representative of the company said.

"Our ferry left Lamma island at 8.15pm to watch the fireworks display out at sea, but within a few minutes, a tugboat [ferry] smashed into our vessel," Yuen Sui-see, operations director for the company, told reporters.

Television pictures showed the red and blue bow of the ferry pointing skywards, surrounded by rescue vessels as government helicopters with search lights circled overhead.

"Over 100 people were sent to five hospitals during the incident, nine of them have sustained serious injuries or are in critical condition," the Fire Services Department [FSD] statement said.

The FSD said the rescue operation was hampered by darkness and "many obstacles onboard".

Cause unknown

"Rescue action will continue overnight as FSD cannot rule out that there are still people inside the vessel or missing," the statement said.

The FSD said 28 boats and two helicopters and 20 ambulances were involved in the rescue operation.

Police said the cause of the accident was not yet known.

A male survivor, wrapped in a blanket on the shore, said: "Within 10 minutes, the ship had sunk. We had to wait at least 20 minutes before we were rescued."

Other survivors said the ship swiftly flooded, trapping many people underwater. Passengers had little time to put on life jackets and some had to break windows to swim to the surface.

"We thought we were going to die. Everyone was trapped inside," said another middle aged woman.

The other passenger ferry, owned by Hong Kong and Kowloon Ferry Holdings, made it safely to the pier on Lamma island with a badly damaged bow after the collision, though several of its passengers and crew were taken to hospital with injuries.

The accident occurred over a long holiday weekend in Hong Kong, which is celebrating the mid-autumn festival and China's National Day on October 1.

Thousands of Hong Kong residents live on outlying islands such as Lamma, which lies about three km southwest of Hong Kong island.

Hong Kong is one of the world's busiest shipping channels, although serious accidents are rare. Investigations are continuing into the accident.

PHOTO CAPTION

Rescuers approach a partially-submerged boat after two vessels collided in Hong Kong October 1, 2012. REUTERS.

Aljazeera