Prime Minister Shinzo Abe set the tone for this year's extraordinary Diet session with a pledge in his opening remarks to overhaul the nation's social welfare system to create one beneficial for all generations.

"We will fearlessly push forward reform that will span the pension, medical, nursing, and labor systems," he told lawmakers assembled in the Diet.

"We will create a social welfare system that will provide security to all generations — from young children to the old," he added.