Japan may cancel the purchase of the F-35 stealth jet in the case of a price hike or delivery delay, Japan's Defense Minister Naoki Tanaka said on Wednesday.

Tanaka told a parliament session that If Japan's need is not satisfied, the ministry will consider cancelling the contract or picking other aircraft.

The Japanese government decided in Dec. to choose the F-35 stealth jet, developed by the United States and eight other countries, as the country's next-generation fighter jet.

The government said it made the final decision by taking into consideration the key factors including the aircraft's performance and cost.

Lockheed Martin's F-35 Lightning II stealth fighter, which had been reviewed along with Boeing's FA-18 Super Hornet and the Eurofighter Typhoon, will replace the country's 40-year-old fleet of F-4s.

Japan plans to acquire a total of 42 jets. It is scheduled to pay about 9.9 billion yen (about 123 million U.S. dollars) per aircraft in fiscal 2012 for an initial delivery of four fighters by March 2017.

Critics in the country have been concerned about the potential increase of costs as the jet is still under development. Tanaka's comments raised doubts about the fate of the order.