Civil servants from the Legal Aid, Rating and Valuation, and Trade and Industry departments swapped their offices for Hong Kong's typhoon-ravaged streets at the weekend after Saola prompted the first-ever use of the new "government-wide mobilisation" protocol.

About 100 civil servants were deployed under the emergency mechanism for work including removing fallen branches and collecting rubbish.

Home Affairs Secretary Alice Mak said she obtained approval from Chief Executive John Lee on Saturday to activate the protocol, with the reinforcements sent to areas including Sha Tau Kok, Tung Chung and Lei Yue Mun.

"Some helped us to send some elderly people who were staying in temporary shelters back to nursing homes. Some helped us to remove some barricades and sandbags that people had put up, so that they could go home safely," Mak said.

"We also had colleagues who worked with the rural committee in Tung Chung to clear a road for villagers to pass through."

Mak added that work was continuing on Sunday to clean up damage caused by the storm, with government staff still in Tai O where water levels were yet to recede.

The government-wide mobilisation protocol was announced in Lee's 2022 policy address to quickly mobilise response units for major crises.

A drill was conducted in February involving about 10,000 staff from various government departments.