* Shareholders have 30 days to decide on cash call participation
* Alitalia's future seen uncertain if Air France-KLM does not take part
* Air France-KLM declined to comment
A source close to Alitalia's biggest investor, Air France-KLM, said it was "50-50" whether it would participate in an emergency share issue to keep the near-bankrupt airline flying because the Italian carrier's business plan did not meet its conditions.
Air France-KLM, which owns 25 percent of Alitalia, approved an emergency 300 million-euro ($408 million) share issue along with the airline's other investors during an all-night meeting that wrapped up after 0100 GMT on Tuesday.
But it is not obliged to participate in the cash call, and has always said it would attach strict conditions before giving any help. Analysts suggest Air France-KLM is dragging its feet in order to secure stricter restructuring concessions from the Italian government and other shareholders. The cash call, part of a wider bailout, is seen as only a stop-gap solution before talks on a possible tie-up between Alitalia and Air France-KLM.
Massimo Sarmi, the head of Italy's post office, which has agreed to commit 75 million euros to the capital increase, was flying to Paris to discuss matters with Air France, a second, separate source told Reuters.
"The position of Air France-KLM is 50:50 at this stage," the source close to the company said. "The business plan presented last week was not suitable, the conditions were not fulfilled, particularly in terms of debt restructuring.
The source added, however, that Alitalia was "of strategic interest" to Air France-KLM.
An Air France-KLM spokesman declined to comment.
Alitalia has not turned a profit since 2002 and came close to being grounded at the weekend after its major creditor Eni threatened to cut fuel supplies.
Rome patched together an emergency 500 million-euro fund, persuading the state-owned post office to commit to providing 75 million euros via a capital increase and banks Intesa Sanpaolo and Unicredit to guarantee up to 100 million euros, while a broader consortium of banks stump up 200 million in existing and new loans.
But the plan still leaves Alitalia dependent on finding at least 125 million euros from its shareholders, who have 30 days to decide whether to sign up. That gives Air France considerable leverage.
The Franco-Dutch carrier was barred from a full takeover of Alitalia in late 2008 by then prime minister Silvio Berlusconi.
Alitalia has lost 700,000 euros a day in the intervening period and Italy's current government and Alitalia's shareholders are now hoping to persuade Air France to up its stake - though there is still considerable political discomfort about any merger. So far all parties have failed to agree financial commitments and business strategy.
Alitalia wants to reposition itself in the higher-margin long-haul market after losing out in regional and domestic routes to competition from low-cost carriers and high-speed trains. That plan appears to clash with Air France's demands for a much tougher restructuring and debt-cutting measures.
Analysts have said the logical way to save the Italian carrier would be for Air France-KLM to take over the operating core of the airline and get rid of the entire Alitalia back-office structure, but that would mean severe cost cuts and job losses, which Rome and unions are likely to oppose bitterly.
If Air France-KLM does not participate in the share issue, it could be overtaken by the Italian post office as Alitalia's top shareholder and its own stake could drop to below 15 percent. This would effectively cost the company its veto power on any new shareholders coming in.
And if Alitalia were to fail, Air France-KLM would lose access to Europe's fourth-largest travel market.
But with Air France in the middle of a tough restructuring itself, that decision will be a close call.
"Without Air France-KLM, there is even less of a future for Alitalia," said Andrea Giuricin, a transport analyst at Milan's Biccoca university. "If Air France-KLM does not put in the money, I want to see which Italian shareholders fill the gap."
The support of Alitalia's domestic investors for the capital increase is also in the balance. Its second biggest shareholder, the Riva family, has had its assets seized in a judicial investigation, including its Alitalia's 11 percent stake.
Alitalia has estimated operating costs of about 10 million euros a day, meaning the emergency cash injection is vitally needed and will not last long.
It said in a statement on Tuesday its board members were ready to resign after the rights issue due to the possible changes in the group's ownership structure.
Alitalia is owned by a disparate group of 21 investors including Intesa Sanpaolo and highway operator Atlantia .