Matsuoka stood with Koizumi, and after the general election he was appointed as a member of the special committee for the privatisation of the postal system.

He worked on some political issues such as Free Trade Agreements with Australia and the beef import problem with the United States.

Matsuoka received much attention when he announced a plan to make certifications for Japanese food restaurants outside Japan.

He got this idea from the Denominazione di origine controllata system in Italy and hoped that this might distinguish pseudo-Japanese food restaurants from genuine ones.

[2] Prior to his death, he faced questions over high utility expenses in a rent-free office – he had claimed more than 28 million yen ($236,600, £118,300).