"We believe the Noda administration to be no longer capable" of effectively conducting the affairs of state, both domestically and internationally, he added.
Neither Mr Noda nor Mr Tanigaki have particularly impressed in their respective roles, however, and both men face leadership elections within their own parties in September.
Whatever the results of those votes, the stalemate in the Diet is likely to continue, meaning that an election is almost certain before the end of the year.
But, given the fractured and shifting nature of Japanese politics, even that is unlikely to bring about the decisive victory for a single party.
According to a study by the Yomiuri Shimbun newspaper, no fewer than 13 parties will put forward candidates for the 479 seats in the Lower House, while a further 34 candidates are running is independents.
