Mr Aso, a straight-talking nationalist, said the Japanese, on the other hand, were trusted because they had "yellow faces" and had "never been involved in exploitation there, or been involved in fights or fired machine guns".

Japan has healthy relations with Arab countries and Iran and imports much of its oil from the Middle East. It is a big contributor of aid to the Palestinian Authority, but also has friendly ties with Israel.

"Japan is doing what Americans can't do," local media quoted Mr Aso as saying in a speech about Japan-sponsored investment in the Middle East. "Japanese are trusted. It would probably be no good to have blue eyes and blond hair. Luckily, we Japanese have yellow faces."

Mr Aso, seen by some as a possible successor to the prime minister, Shinzo Abe, is no stranger to controversy.

In 2001 he said a member of the burakumin, Japan's underclass, could never lead the country. He later angered Japan's indigenous Ainu population by describing the country as unique in being "one nation, one civilisation, one language, one culture and one race". While economics minister, he said he wanted to turn Japan into a country where "rich Jews" would want to live.

In 2003, he sparked protests when he praised imperial Japan's often brutal colonial rule of the Korean peninsula from 1910 to 1945, and last month he described the US post-invasion plans for Iraq as "very immature".