Kuwaiti Oil Minister Adel Khaled al-Subeih has postponed a visit to Japan that was scheduled to begin today, Japanese government sources said Tuesday.

The main factor behind the decision was the fact that Japanese oil firm Arabian Oil Co. is still encountering difficulties in its talks with Kuwait over the extension of its drilling rights on the Kuwaiti side of the Khafji oil field. , the sources said.

Meanwhile, Hirofumi Kawano, director general of the Natural Resources and Energy Agency, is currently visiting Kuwait in an effort to help Arabian Oil and the Kuwaiti government reach an accord before the deadline of the negotiations Thursday. , they said.

The two sides have reportedly agreed to a plan under which Arabian Oil will drill the oil field in Khafji on behalf of the Kuwaiti government -- rather than owning concessions for the drilling -- and receive commission fees from Kuwait under a technical service contract, they said.

But the two sides are still deadlocked over other issues, such as the length of any new contract.

The current contract between Arabian Oil and Kuwait, which will expire in January 2003, is a comprehensive one in which the oil company has rights over nearly everything.

Kuwait wants to change the current contract to a service agreement under which the government will let Arabian Oil handle drilling operations.