BEIJING (Reuters) - Two short crude oil pipelines in China operated by Sinopec Group are shutting temporarily due to worries over safety, the Chinese authorities said.

Sinopec has been ordered to shut the 179km Linyi-Cangzhou pipeline and a 40km pipeline from the Tanggu oil depot to Dagang in Tianjin by Nov 20, the State Administration of Work Safety said on its website late last week.

The authorities said that unannounced inspections had found numerous problems, including "stress corrosion and fatigue damage".

Sinopec said on Friday through its official social media account that the two pipelines had earlier been closed for repairs and that the work safety regulator had approved the shutdowns in September.

However, it was unclear whether they had been reopened since then and would need to be closed again. Sinopec was not immediately available for comment on Monday.

Refinery throughput in northern China had not been affected, the company said on Friday.

The Linyi-Canzhou pipeline passes through populated urban neighbourhoods. The Tianjin pipeline is mostly near water and was corroded.

Sinopec will have until Dec 10 to address the issues, authorities said.

Last December, the authorities launched a nationwide safety probe in the oil and gas sector after a pipeline blast killed 62 people.

Checks on some 3,000 petrochemical companies and oil storage sites found nearly 20,000 potential hazards.