Many airlines, including flagship home carrier Cathay Pacific Airways Ltd, South African Airways and Malaysia's AirAsia Group Bhd have cut flights to and from Hong Kong temporarily as a result of sometimes violent anti-government protests that have led to a sharp fall in tourist and business travel demand.

More than 5,800 people have been arrested since the unrest broke out in June over a proposal to allow extraditions to mainland China, the numbers grew in October and November as violence escalated.

Under more normal conditions, it is tough for airlines to get take-off and landing slots at Hong Kong's airport because it lacks capacity until a third runway will come into operation in 2024.

A "use-it-or-lose-it" rule stipulates an airline normally only keeps slots out of historic precedence if it can demonstrate it used them at least 80% of the time in the previous airline scheduling season.

The current winter season, which began on Oct. 27, ends on March 28, 2020.

Hong Kong's Civil Aviation Department said in a statement to Reuters on Thursday evening that in order to provide airlines with greater flexibility in aircraft deployment to deal with the fall in passenger demand, the "use-it-or-lose-it" rule had been temporarily suspended for the winter season.

Airport Authority Hong Kong reported declines in October of 13% in passengers and 6.1% in the number of inbound and outbound flights - the steepest falls since the unrest began.

(Reporting by Jamie Freed in Sydney; Editing by Marguerita Choy)