Japan's Diet has enacted a bill designed to help secure financial resources to strengthen the country's defense capabilities.

The Upper House plenary session approved the bill on Friday with a majority of votes, including those from the ruling Liberal Democratic and Komeito Parties.

The passage of the bill was seen as one of the government's top priorities in the current Diet session.

Opposition parties, including the Constitutional Democratic Party, Nippon Ishin Japan Innovation Party, the Japanese Communist Party and the Democratic Party for the People, voted against.

The legislation stipulates creating a fund within the government's general account to boost defense-related spending. Non-tax income from sales of state properties, money created through spending reform and surplus from financial results will be included in the fund for use beyond a single fiscal year.

The opposition camp says that the government's defense budget increase plan is still based on the assumption of raising taxes.

Before the Upper House vote on Friday, lawmaker Shiba Shinichi of the Constitutional Democratic Party criticized the government for being irresponsible. He noted that it failed to show any prospects for spending reforms that can secure the necessary funds.

He referred to the government's plan to use a special income taxation scheme for reconstruction of areas hit by 2011 earthquake and tsunami disaster to boost defense spending. The opposition lawmaker criticized the plan for being misleading, as if it's trying to give the appearance that there will be no new taxation to cover the defense spending increase.