The Diet returned to business as usual Tuesday as major opposition parties ended their 18-day boycott of parliamentary debates over the government's handling of cronyism scandals involving Prime Minister Shinzo Abe.

The ruling bloc is now expected to hurry to pass its labor reform bill, promoted by Abe as his top priority in the ongoing Diet session through June 20, while members of the opposition are expected to grill the government over favoritism allegations against the prime minister in connection with school projects.

Lawmakers of the Constitutional Democratic Party of Japan and other opposition parties attending the day's plenary session, with the government explaining a set of bills to ratify the Trans-Pacific Partnership — a free trade pact that Japan and 10 other member counties signed in March following the United States' withdrawal.