Development Secretary Bernadette Linn on Saturday dismissed suggestions that there was negligence involved in the inspection of unauthorised construction, after unapproved building works were found at three luxury homes on the Redhill Peninsula in Tai Tam.

Speaking on an RTHK programme, the minister said authorities are gathering evidence and will make prosecutions accordingly. They will also conduct large-scale inspections at housing estates.

Linn said the high-end residential estate was not on the list of proactive inspections, but priority will be given to those located by the sea and near hillsides in future.

"In terms of these kinds of houses, I think it is logical that for the prioritisation, we will accord priority to those facing the sea and on the slope," she said.

"Because for houses built on the slope, if there are any unauthorised building works, there will be a slope stability angle. So the public safety is an important factor that we have to take into account."

The minister added that 18 projects have been designed to improve the city's drainage infrastructure in areas such as Wong Tai Sin and Eastern District, to gear up for unprecedented bad weather.

"In the design of our drainage system, we have adopted standards which are comparable and in some areas exceeded standards adopted by our neighbouring jurisdictions," she said.

"The heavy rainstorm that we had last week and in the past few days in selected locations reminded us that climate change can really be very extreme and can come at a time well before our expectation. This means that we have to proceed earnestly with our study looking ahead to assume different extreme weathers and what we should do."

Speaking on another radio programme, home affairs chief Alice Mak and transport minister Lam Sai-hung said the government-wide mobilisation protocol has been effective in dealing with the downpours.

Mak said there have so far been 2,300 applications from residents and merchants who experienced losses due to the severe storm, and officials will speed up vetting of these applications.