A senior Japanese trade official said the Association of Southeast Asian Nations should speed up efforts to integrate the regional economy in a bid to call back Japanese investment.

"It is important for ASEAN, and also desirable to Japan, that ASEAN further accelerates integration," Hidehiro Konno, the Ministry of Economy, Trade and Industry's vice minister for international affairs, said in an interview Wednesday with Kyodo News.

Konno was passing through Bangkok on his way to attend a Friday meeting of economic ministers from ASEAN plus China, Japan and South Korea in Cambodia on behalf of Economy, Trade and Industry Minister Takeo Hiranuma. The meeting follows an informal gathering Thursday of ASEAN's economic ministers.

Hiranuma will skip the meeting in Siem Reap for political reasons, ministry officials said, referring to the onset of the new government under Prime Minister Junichiro Koizumi and the ongoing session of the Diet.