In his blog yesterday, Wai said the SAR is seeing more and more buildings getting older but fewer and fewer owners making a habit of building maintenance.

"It's usual to see landlords having no financial plans or reserves for regular maintenance and repair," he said.

"For buildings 30 years old or younger, owners don't have the sense of preventive maintenance. When these structures reach 40 years old, I'm afraid they start to go out of shape."

Wai said the URA has spent much of its resources to help landlords push forward building repairs and maintenance, but all of them had to be conducted by means of promotion and encouragement.

"The URA has no legislative or law enforcement powers," he said. "It has used all possible means, but still can't achieve the outcome of getting landlords to pay attention to building maintenance and proactively plan for regular maintenance."

"This is where society should step in and conduct in-depth discussions on whether we should amend laws" he said.

Calling it the "ultimate solution," Wai said possible legislation should require landlords to come up with maintenance plans, budgetary and funding arrangements, and also conduct compulsory inspections regular ly.

He said the authority will promote, facilitate, execute and plan for "a new culture of preventive building maintenance."

Apart from adding a preventive maintenance requirement into the terms of the second phase of Hung Hom's Starter Homes pilot project eResidence, Wai said the URA is looking to use new building methods and materials so the buildings can withstand natural erosion for up to 75 years.

Wai said it is also planning to upgrade its urban renewal information system to use big data to analyze the distribution of aging buildings in different districts to plan for maintenance by clusters instead of by blocks.