The Tianjian port free trade zone, the largest in north China, reported a robust economic growth of 46.5 percent year-on-year in 2007, local authorities said.

The zone's gross domestic product (GDP) reached a record high of 30 billion yuan ($4.1 billion) last year, said Feng Zhijiang, the zone administrative commission's director.

The total industrial output value hit 39.6 billion yuan, up 55 percent.

Covering an area of five square kilometers at the Tianjin port, the free trade zone has currently 2,000 registered trade companies and 300 logistics firms.

Feng said the zone would strive for a 42 billion yuan GDP this year.

China has about 15 free trade zones along its east-south coastal areas. They enjoy a number of preferential polices in tariffs and investment opportunities.