TOKYO - Japan's defence minister says Tokyo may cancel its plans to buy dozens of F-35 stealth fighter jets from the United States in a multi-billion dollar deal if the prices continue to rise or if delays threaten the delivery date.

Defence Minister Naoki Tanaka told Parliament Wednesday that failure by manufacturer Lockheed Martin to deliver on time at the current price levels would force Tokyo to consider switching to a different aircraft.

Japan announced late last year that it would purchase 42 F-35 jets in a deal expected to cost more than $5 billion. The F-35 is set to become the centerpiece of the U.S. military and allied air forces around the world. But the program has been plagued by delays and cost overruns.