Chinese customs said on Tuesday it will amend the way it supervises crude oil imports as part of a broader effort to boost efficiency, allowing cargoes to clear customs before quality inspections have been finalised.

Key import oil terminals along China's coast, including the provinces of Shandong, Zhejiang and Guangdong, suffered severe congestion between May and August as record crude purchases arrived in the country.

Effective from Oct. 1, importers will be allowed to start offloading oil once customs officers have collected key information and a sample of oil, the General Administration of Customs said in a statement its website.

Importers will still only be allowed to use or sell the oil once subsequent laboratory tests are completed.

Any problems related to safety, quality or evidence of trade fraud will be dealt with as normal, customs said.