Singapore Airlines has urged its customers booked on flights in and out of Hong Kong and Guangzhou on Sunday and Monday to defer non-essential travel, due to the impact of Typhoon Usagi.

In a Facebook post, the airline said flights on these two days may be delayed or cancelled. It will waive administrative fees and penalties for refunds, re-booking or re-routing, for customers holding confirmed tickets issued on or before September 22 2013, for travel to and from Hong Kong until September 23 2013.

SIA said it will continue to monitor the situation closely and provide updates.

Meanwhile, Cathay Pacific has also advised passengers to postpone non-essential travel from Sept 22 to Sept 23, and cancelled all flights into and out of Hong Kong.

It, too, will waive re-booking fees for tickets issued on or before September 21, for travel to or from Hong Kong till September 23.

United Airlines has cancelled its flights between Singapore and Hong Kong.

Typhoon Usagi has battered southern Taiwan and the northern Philippines with rain and winds of more than 200 km/h, and is expected to hit Hong Kong on Sunday.