Secretary for Housing Winnie Ho on Tuesday said special measures are being taken in some of the highest and lowest-lying areas of Hong Kong as Super Typhoon Ragasa barrels towards the city.

On a radio show, Ho said she has been leading teams in inspecting public housing estates most at risk.

At On Tai Estate in Sau Mau Ping, one of the city's highest areas, steel frames of rooftop solar panels have been reinforced.

Meanwhile, flood barriers have been put in place at Wong Tai Sin Estate, one of the SAR's low-lying areas, to prevent a repeat of heavy flooding in 2023.

"My colleagues have already installed two-thirds of the flood barriers there. It's all done," Ho said.

"As for the remaining part, there is a main passage that many people use to get to the MTR. That will be completed today. We're confident we can do that in about 15 to 20 minutes.

"And if the rain really comes early, they will install it as soon as possible so we don't have a repeat of what happened before," she added.

Meanwhile, Ho warned that wooden boards, nets and scaffolding at construction sites need to be properly stored for when the storm hits.

"The most important issue is if the scaffolding might fall off, for example, if it's lowered or rolled up, it can block the winds and make the [structure] just like a sailing boat, so it's very easy to tear down," she said.

"Therefore, it's vital to put away nets and materials and tie them all up."