BEIJING, Aug. 14 -- China will expand its export tax rebate pilot program to eight more ports at the beginning of next month to boost exports amid an economic slowdown.

The new tax rebate policy will be applied to exported container goods with customs clearance at water ports in the cities of Nanjing, Suzhou, Lianyungang, Wuhu, Jiujiang, Qingdao, Wuhan and Yueyang, according to a joint document by the Ministry of Finance, the General Administration of Customs and the State Administration of Taxation published on Thursday.

The exporting containers must be transferred and depart via the Yangshan Free Trade Port in Shanghai, according to the document.

Taxes will be refunded at those ports of loading to qualified exporting enterprises whose tax payment credit is rated B or better by both tax and customs authorities, the document said.

Such a policy does not apply to companies blacklisted under the country's tax rebate review system.

Transport enterprises looking to take advantage of the new policy are required to have a payment credit rating of B or better by tax authorities and cannot have previous smuggling or regulation violation records within three years.

Container carriers must also be equipped with navigation, position and video surveillance devices that would enable customs authorities to monitor the process, according to the document.