In 1997, Japan estimated that 700,000 chemical weapons remain in China, with 670,000 alone in Harbaling, Jilin Province, according to a document it filed with an international organization.

Tokyo, however, may make a revision due to later surveys, Hosoda said during a news conference.

The Chinese government is expected to agree to a lower estimate because Chinese Vice Foreign Minister Wu Dawei said in a recent meeting with a Japanese official that China has confirmed a total of 400,000 chemical weapons in 15 provinces, including Jilin, Hosoda said.

The initial estimate was filed with the Organization for the Prohibition of Chemical Weapons, an international body set up in 1997 by the countries that joined the Chemical Weapons Convention.

Under the convention, Japan is obliged to dispose of the chemical weapons in China by 2007. It is planning to build disposal facilities in Jilin Province under a joint project with China.