* Lower house defeats opposition motion to scrap F-35
* Parliament to vote on further stages of investment
* Defence minister says F-35 to replace obsolete fleet
By Steve Scherer
ROME, June 26 (Reuters) - Italy's ruling coalition averted a split over a motion to scrap its purchase of 90 Lockheed Martin F-35 fighter jets on Wednesday by agreeing to seek parliament's approval before going ahead with further spending on the programme.
The awkward right-left governing bloc, formed two months ago to end a political stalemate that followed February's deadlocked national election, risked fragmenting over a vote to pull out of the fighter programme first agreed more than a decade ago.
The lower-house motion, presented last month and supported by opposition groups and some members of Prime Minister Enrico Letta's centre-left Democratic Party (PD), was gathering further support in the PD even as late as Tuesday, the eve of the vote.
The PD said it would cut spending on the programme before the election but its coalition partner, the centre-right People of Freedom party (PDL), supports the purchase.
After a two-hour meeting on Wednesday, the ruling parties came up with a new motion that the government then supported.
The new motion called on the government to push for further integration of European Union defence projects to reduce costs, and says it should seek the support of parliament before advancing to further stages of the fighter purchase.
The government-backed motion passed 381 to 149, while the opposition motion in favour of abandoning the F-35 was defeated. Both motions were non-binding.
The F-35 is a delicate issue for Letta's coalition, which is struggling to manage a huge public debt and limit its budget deficit to a forecast 2.9 percent of gross domestic product this year, a fraction below the European Union's 3 percent ceiling.
Before Wednesday's vote, Defence Minister Mario Mauro again defended the F-35 purchase, saying the new fighters would replace an ageing fleet of obsolete aircraft.
Italy plans to spend 11.8 billion euros ($15.43 billion) on the jets over 45 years, starting in 2015, Mauro said on Tuesday.
The deal includes maintenance contracts for state-controlled defence group Finmeccanica, as Italy's aerospace industry is a development partner in the F-35 project and Italy has already invested about 2 billion euros in it.
Last year, Italy cut its F-35 order to 90 warplanes from the 131 it had originally agreed to buy, a move it said would save 5 billion euros as it sought to reduce defence spending to shore up its accounts during the economic slump.