Authorities on Sunday said it aims to partially reopen on Monday a stretch of road in Sham Shui Po that was hit by heavy subsidence.

Officials had cordoned off a section of Hai Tan Street after part of the carriageway plunged into a four-metre-deep hole that measured about eight by 12 metres.

The Water Supplies Department earlier noted that there was no damage to a water main but a sewer and a storm drain two metres down have been affected.

"The water supply is fine, but we found that there's partial damage to the drain pipes. Mainly it's water and soil loss after heavy rains in recent days," said Roger Wong, the department's director.

"Now we are trying to fix the issues to ensure the safety of all residents," he added, noting that an investigation into the cause of the subsidence is under way.

People in the area on Sunday said the closure of the stretch of road between Yen Chow Street and Kweilin Street was not too inconvenient.

"I mean, of course there's some impact as I need to take a bus to come back, so I am getting off [at a nearby station], but it's just one block away, so it's still okay," one pedestrian on his way to yum cha told RTHK.

But a taxi driver said he might need to circle around to find alternative routes.

"Usually I drive straight ahead on this road, and I use this path very frequently. Now I have to maybe take another two or three minutes when using another route," he said.

Scott Leung, a lawmaker representing the Kowloon West constituency, urged authorities to find the cause of the incident and step up work to survey underground pipes.

"Can we ramp up the surveying of drainage pipes and water pipes in future, so that subsidences won't occur because things can get out of order underground without people noticing," he said.

"The Water Supplies Department already has plans to inspect and repair water pipes in old areas, but other departments also need to do this for other pipes,” he added.