WASHINGTON (Reuters) - Any further cost increase or problems with the $382 billion F-35 Joint Strike Fighter would mean reduced Pentagon purchases of the new warplane, being developed and built by Lockheed Martin Corp, U.S. Air Force Secretary Michael Donley told a Senate committee on Tuesday.
Donley said the latest restructuring of the program should allow the F-35 to continue with the "least risk."
But he said the Pentagon's F-35 program office and Lockheed had been told there was "no more money to put against contract overruns or problems."
"To the extent that there continue to be cost growth or challenges ... We'll have to take down the number of aircraft that we have planned in procurement to pay for that work because no more money is going to be migrating into this program," Donley told the Senate Armed Services Committee.
The Pentagon's fiscal 2013 budget calls for postponing production of 179 F-35 planes to save $15.1 billion over the next five years, as the U.S. military begins to implement $487 billion in spending cuts over the next decade.
Slowing development would also avert costly retrofits if further issues arise during flight testing.
Donley said the decision to slow down production would probably add some cost to the program, but he said it would also save money if additional problems came up during testing, necessitating retrofits of planes already produced.
"It adds time to the program and that usually means costs," he said.
He said the Pentagon was working on an adjusted cost estimate for the program, with details to be shared with Congress later this spring.
Pentagon leaders have said they are not scaling back their plans to buy a total of 2,443 F-35s for the Air Force, Navy and Marine Corps, but Donley's comments indicate the procurement target may not hold indefinitely if additional issues arise.
Current plans call for the Air Force to acquire 1,763 of the stealthy fighter planes, while the Navy and Marine Corps would get a combined total of 680.
Lockheed is building three variants of the radar-evading supersonic warplane for the U.S. military and eight countries that are helping to fund its development -- Britain, Australia, Canada, Turkey, Italy, Denmark, Norway and the Netherlands. Israel and Japan also plan to buy the new fighter.
U.S. officials last week sought to allay concerns over delays and escalating costs for the F-35, telling the eight partner nations at a meeting in Australia that there would be no further delays on the program.
(Reporting By Andrea Shalal-Esa; editing by John Wallace)