Japan's financial services minister was found dead at his home on Monday in what police believe was a possible suicide, media said.

Tadahiro Matsushita, 73, who was also the state minister in charge of postal reform for Prime Minister Yoshihiko Noda, was found collapsed at his house in Tokyo and confirmed dead at hospital shortly afterwards, public broadcaster NHK said.

Kyodo News and Jiji Press, citing police sources, reported that Matsushita was thought to have taken his own life.

"I am very shocked at the tragic news," Noda told reporters, quoted by Jiji. "I don't know what to say."

Matsushita was first elected to a lower house seat in 1993 through the Liberal Democratic Party.

But his opposition to postal privatization, pushed by then-prime minister Junichiro Koizumi, forced him out of the LDP to join the People's New Party, now Noda's junior coalition partner.

He was appointed to the post of financial services minister and state minister in charge of supervising the postal privatization in June. (AFP)