An investigation is under way into a landslip that left sand, mud and debris covering a popular walking path in King's Park Garden, Yau Ma Tei, yesterday.
Yau Tsim Mong district council vice-chairman Edward Leung Wai-kuen said it could have been caused by water from a luxury estate - King's Park Hill - above the slope.
'A morning exerciser complained that someone released water onto the slope from the private housing estate at about 8am, about an hour before the landslide. But it was unknown who released water and why,' he said.
Another possible cause could be water from the pumping room of the estate's swimming pool. 'Workers from related departments told me that the pump room was flooded with one metre of water,' he said.
Yesterday, Henderson Land Development subsidiary Well Born Real Estate Management, which is responsible for King's Park Hill, confirmed that the pump room was flooded with water and that it was investigating.
Fire and police officers were called to the scene at about 9am when the 10-metre slope, between the estate and True Light Girls' College, collapsed, damaging railings and covering part of the walkway.
About 30 firefighters searched the area to ensure no one was trapped.
'It's a popular walking path for elderly morning exercisers,' Leung said. 'It's lucky no one was buried and no casualties were involved.'
The Architectural Services Department, which is responsible for the slope, said the previous regular repair and inspection was carried out in December.
A spokesman said the initial investigation showed the landslide was caused by a large amount of water.
The Architectural Services Department, Civil Engineering and Development Department and other related departments are investigating.