China has launched a nationwide probe into the safety of its oil and gas pipelines following a deadly blast that killed 62 people in the eastern coastal city of Qingdao last month, the country's safety watchdog said on Friday.

The investigation will focus on "hidden dangers" in the country's oil, gas and petrochemical sectors and will be completed by March of next year, the Chinese cabinet commission responsible for work safety said in a notice posted on its website (www.chinasafety.gov.cn).

The explosion at the Dongying-Huangdao II pipeline owned by top Asian refiner China Petroleum & Chemical Corp (Sinopec) in Qingdao is believed to have been caused by oil leaking into city drainage facilities, according to a preliminary investigation.