* Government wants to go ahead with purchase
* Cost of 90 planes seen topping 10 billion euros
By Steve Scherer and Roberto Landucci
ROME, May 30 (Reuters) - Italian opposition parties and some lawmakers from the ruling Democratic Party called on the government on Thursday to abandon its plans to buy 90 Lockheed Martin F-35 fighter jets.
Italy's total planned investment in the new Lightning II Joint Strike fighters (JSF) exceeds 10 billion euros ($12.97 billion) even though it cut its order last year to 90 aircraft from the 131 it had originally pencilled in to buy more than a decade ago, a move it said would save 5 billion euros.
The opposition 5-Star Movement, the Left Ecology Liberty (SEL) and 13 members of Prime Minister Enrico Letta's Democratic Party (PD), one of two main components of the right-left coalition, now want to scrap the order completely.
"We can easily do without the F-35," said Giulio Marcon, an SEL lawmaker. "The government should make a responsible gesture and use these resources to increase welfare spending and create jobs."
With Italy mired in recession and struggling with public finances, the money saved by eliminating a single F-35 could be used to build 387 day care centres or renovate 258 schools, according to a motion signed by 158 parliamentarians in the lower house Chamber of Deputies.
The PD said it wanted to cut spending on the programme during the campaign for national elections last February, but has since formed a government with Silvio Berlusconi's People of Freedom (PDL) party, which supports the F-35.
The F-35 investment "should be revised, just as we all said in the election campaign," Giuseppe Civati, one of 13 PD members who signed the motion, told Reuters.
Civati, a frequent critic of his own party, accused the PD and former prime minister Mario Monti's Civic Choice party of reneging on campaign promises to cut spending on the jet.
Defence Minister Mario Mauro, a member of Monti's party, said last week the month-old government wanted to go ahead with the purchase, saying, "we need defence tools to guarantee peace".
The deal includes a provision to give maintenance contracts to state-controlled defence group Finmeccanica as Italy's aerospace industry is a development and production partner in the F-35 project and Italy has already invested about 2 billion euros in it.
However, the project is seven years behind schedule and 70 percent over initial cost estimates. Other countries have also cut their provisional orders for the plane because of the economic crisis that has shrunk defence budgets worldwide.