By Duncan Bartlett BBC World Service business reporter

Two airlines are fighting for the right to fly between Hong Kong and mainland China.

At present only one airline, Dragonair, is allowed to take passengers across the border.

However its larger rival, Cathay Pacific, wants to set up flights from Hong Kong to Shanghai, Beijing and Xiamen.

Dragonair is not happy with the prospect of competition so the dispute is now being heard by the authorities.

Competition

The rapid growth of China's economy has led to a big increase in demand for air tickets between Hong Kong and the mainland.

However, Dragonair says it is not strong enough to cope with the competition and, it says, the routes will not sustain two airlines.

Dragonair says the routes will not sustain two airlines

Dragonair has taken its case to Hong Kong's High Court in the hope that the territory will rule that only one airline can operate the routes to China.

Cathay says there is clearly room for both operators.

Fifteen years ago there was only one or two flights a week between Hong Kong and Shanghai - now there are 56.

Cathay says competition will bring prices down and that will be good for travellers.

It is expected to take five days for the two sides to present their legal arguments after which the court is set to outline what Hong Kong's Air Transport Licensing Authority can do.

After that the case must be heard in Beijing before a final decision can be made.