Three Chinese warships will leave port later this week to join a growing international anti-piracy force off the coast of Somalia, Chinese officials have said.

Two destroyers and an accompanying supply vessel will set sail on Friday from their base on the southern Chinese island of Hainan, Huang Xueping, a defence ministry spokesman, told reporters in Beijing on Tuesday.

He said the deployment would help to protect Chinese ships transiting the area, but also that the Chinese navy was willing to work with others battling pirates in the region, including warships the US, Russia and the European Union.

Piracy off the Horn of Africa has taken an increasing toll on international shipping, especially in the Gulf of Aden, one of the world's busiest sea lanes.

This year more than 40 vessels have been hijacked off the Somali coast, with pirates taking an estimated $30m in ransom payments.

Last week Chinese foreign ministry officials said about 20 per cent of Chinese ships travelling through the area had come under attack.

International security

Although China has a huge global commercial maritime presence, the deployment of the three warships will be China's first major naval operation abroad.

Until now the Chinese navy has primarily focused on defending the country's coastline, limiting operations abroad to port calls, goodwill visits and exercises with other navies.

But with China's growing global clout there have been calls for Beijing to take a greater role in international security affairs.

However, a senior Chinese military official played down the significance of the Somalia mission, saying the deployment did not show any major shift in policy.

"This is only an escorting operation to the Gulf of Aden and Somali waters," Senior Captain Ma Luping, director of the Navy Bureau of the General Staff Headquarters Operations Department, said.

"It does not indicate any change in the strategy of the Chinese military."