Domestic crude rubber stocks, which are compiled by the Rubber Trade Association of Japan, have stayed at low levels since May as domestic end-users have turned to those inventories after delays in rubber shipments from Thailand.
Thailand, the world's top producer and exporter of natural rubber, has been hit this year by drought and violence in key rubber producing areas.
Crude rubber stocks in Japan hit a record low of 7,106 tonnes in August. Reflecting tight supplies, rubber futures prices on the Tokyo Commodity Exchange have been buoyant this year.
The benchmark June 2006 contract ended on Wednesday's session at 213.2 yen per kg, up 1.0 yen from Tuesday's closing price. TOCOM's benchmark rubber contract hit a 17-year high of 227.6 yen on December 12, up 92 percent from this year's low of 118.3 yen marked in January.