The ruling bloc rammed a hastily compiled bill through the Lower House welfare committee on Wednesday, steamrolling testy opposition lawmakers as it raced to put a lid on the explosive pension data fiasco.

The unilateral action by the Liberal Democratic Party and junior partner New Komeito kick-starts the passage of legislation seen as critical to the coalition's efforts to control damage from scandals in the runup to the Upper House election in July.

The opposition camp, led by the Democratic Party of Japan, attacked the two parties for scheduling only a day of deliberations on what has been termed a weak bill to remove the five-year statute of limitations on pension claims.