China's civil aviation authority and airlines have been sparing no efforts in accommodating passengers in Hong Kong affected by flight cancellations.

Hong Kong International Airport was forced to suspend all check-ins for departing flights for a second straight day on Tuesday afternoon as protesters returned and brought chaos to the airport, hours after it resumed a limited number of flights in the morning.

The Civil Aviation Administration of China said that efforts will be made to increase the transfer capacity of airports in the Guangdong-Hong Kong-Macao Greater Bay Area to avoid disruption to trips between the mainland and Hong Kong following recent disruptions at the special administration region's airport.

It will enhance flight capacity as well as provide easier access for passengers to reschedule or refund tickets, the administration said on Monday.

Mainland airlines such as Air China, China Eastern and China Southern, all stepped up their efforts to handle inconvenienced passengers. The airlines said Tuesday they will fully refund or help with ticket bookings for passengers affected by cancellations.

Air China, which canceled 22 flights on Monday and Tuesday, said it will arrange extra flights between Beijing and Shenzhen, Guangdong province, on Tuesday to cope with the passenger demand due to the protest at Hong Kong's airport.

The ongoing situation has disrupted travel plans for many passengers and caused inconvenience.

Passengers also expressed deep concerns about their recent trips to Hong Kong amid a massive backlog of flights.

Huang Yanheng, 29, who works at a consulting company in Beijing, plans to travel to Indonesia next week and needs to transfer in Hong Kong.

"I planned the trip almost half a year ago but the woes at the airport still remain. Therefore I had to cancel my trip," he said, adding that he will try to avoid nonessential travel to Hong Kong.