Protesters have planned to converge in their thousands for the second day running on Hong Kong's global airport at 1pm (local time), after their pro-democracy demonstrations yesterday caused all flights that had not completed check-in procedures to be cancelled, together with arriving flights that had not yet taken off.
It has fallen 6 per cent since the protests began in June.
A large convoy of military trucks and cars have been driven into Shenzhen, 25kms from Hong Kong, in readiness for another day of protests by the pro-democracy demonstrators at Hong Kong International Airport.
Hong Kong's flagship airline Cathay Pacific, on Tuesday morning, listed more than 200 flight cancellations and urged customers to postpone non-essential travel from Hong Kong. "It's the only way I think you'll put a cap on this and get back to peace and stability in Hong Kong".
The airport disruptions are an escalation of demonstrations aimed at what many Hong Kong residents see as an increasing erosion of the freedoms they were promised in 1997 when Communist Party-ruled mainland China took over what had been a British colony.
United Nations human rights chief Michelle Bachelet has issued a statement calling on Hong Kong authorities to exercise restraint and to investigate incidents involving tear gas fired at the protesters.
"Our Intelligence has informed us that the Chinese Government is moving troops to the Border with Hong Kong".
Cathay became embroiled in the protests after China's civil aviation regulator demanded the airline suspend personnel who were engaged in or supported "illegal protests" in Hong Kong from staffing flights into its airspace, citing safety concerns.
Some protesters have left the airport after the police arrived, according to SkyNews.
In an unusually strong statement, Hong Kong company Swire Pacific, who own flagship airline Cathay Pacific, have called for the "restoration of law and order" in the city.
"The situation in Hong Kong in the past week has made me very anxious that we have reached this unsafe situation". By Tuesday afternoon in Hong Kong, however, the crowds of protesters had returned.
Commercial director Brent Thomas said as well as being a popular destination in itself, Hong Kong is a busy transit stop for people heading to and from Europe.
The official state news agency Xinhua warned in a commentary Tuesday that "violent radicals" were pushing Hong Kong into an "abyss".