Japan's main opposition party, the Constitutional Democratic Party, submitted a no-confidence motion against Finance Minister Suzuki Shunichi on Tuesday.
The party is protesting a bill that would allow the government to establish a fund aimed at strengthening Japan's defense capabilities.
It obstructed a vote on the bill that was scheduled to be held in the Lower House Financial Affairs Committee on Tuesday by submitting the motion.
The government and ruling camp regard the bill as a key piece of legislation, and they want to have it enacted during the current session of the Diet. Debates on the bill started in the Lower House plenary session in April.
In the motion, the CDP says defense spending increases are interfering with financial resources earmarked for the reconstruction work in areas affected by the earthquake, tsunami and nuclear disaster that occurred on March 11, 2011.
They say the bill should be the foundation of Japan's security. But they say they have no choice but to call it defective, as it has many problems. They add that the finance minister is trying to steamroller it through.
The party's Diet affairs chief Azumi Jun said the increased defense budget is disproportionately large compared to Japan's financial circumstances.
He said lawmakers should not secure funds by taking away money, which should be spent on welfare and people in need.
He said the bill should be scrapped. He added that he will do everything he can to postpone the vote.
Ochi Takao of the main ruling Liberal Democratic Party is a senior member of the Lower House Financial Affairs Committee.
He told reporters that the bill has been debated for a month. Ochi said that he will make an all-out effort to have it passed in the Lower House and then sent to the Upper House.