Members of the Cabinet on Saturday approved the convening of a special three-day Diet session from Tuesday to select a prime minister, launch a new Cabinet and hold deliberations.
Prime Minister Yoshiro Mori is expected to retain his post during the vote Tuesday with support from three parties of the ruling coalition -- the Liberal Democratic Party, New Komeito and the New Conservative Party.
A new Cabinet is also scheduled to be launched that day.
The session follows the June 25 House of Representatives election.
The opposition parties want time allocated in the session to ask questions concerning the arrest Friday of former Construction Minister Eiichi Nakao, who is suspected of taking 30 million yen in bribes.