Japan sees little chance of the oil spill from a stricken Iranian tanker that sank on Sunday in the East China Sea reaching its shores, an official at the nation's Environment Ministry said on Tuesday.

The large tanker Sanchi sank in the worst oil ship disaster in decades and produced a large oil slick, Chinese media and Japanese authorities said on Monday, as worries grew over damage to the marine ecosystem.

The vessel's crew of 30 Iranians and two Bangladeshis are all believed to have perished in the incident.