The Observatory said late on Saturday that it would consider raising a higher storm signal on Sunday, confirming that the Strong Wind Signal Number 3 would remain in force until at least noon with the slow-moving Typhoon Koinu continuing to edge past Hong Kong.

The forecaster said that as of 9pm, the storm remained about 145 kilometres southeast of Hong Kong, and it was forecast to move west slowly across the coastal waters of Guangdong, with wind directions changing in the territory.

"Places that have been sheltered before will become more exposed to high winds," said Chan Ying-wa, a senior scientific officer. "There may be occasional gale winds over some places.

"Depending on the change in local wind strength by then, the Observatory will assess the need for issuance of higher tropical cyclone warning signals."

Transport minister Lam Sai-hung had earlier said the Emergency Transport Co-ordination Centre is closely monitoring traffic conditions across Hong Kong.

The Education Bureau had announced that classes of kindergartens and schools for children with physical or intellectual disabilities were suspended.