On Tuesday the Council of States approved the defence ministry purchase by 22 votes to 20 but blocked the necessary funds.
One-off expenses of over 20 million francs need to be approved by an absolute majority in parliament.
The Council of States failed by just one vote to permit the release of the funds, Tages-Anzeiger reported.
The government opted in November 2012 to renew its fighter jet fleet with 22 Gripen jets from Sweden. The price agreed was 3.1 billion francs.
The purchase has been hotly debated for months. But Defence Minister Ueli Maurer told the NZZ he was “very surprised” by the decision.
Apart from the fundamental question about whether the aircraft are actually needed, there is also the issue of guarantees from the Swedish government.
The new series of Gripen jet is still being developed by manufacturer Saab.
Until last week it had looked as if the Council of States would wave the purchase through without question, Tages-Anzeiger said.
The Council’s security commission had already approved the deal.
“We were all surprised by the result,” said Social Democrat member of the house Roberto Zanetti, who considers the new aircraft unnecessary.
Zanetti said there had not been much criticism of the planned purchase during the debate in the chamber.
He said the result was a sign of the apparent uncertainty among the centre-right parties, who had appeared satisfied with the defence ministry answers to questions raised.
“Some centre-right parliamentarians had spoken about the risks attached to the deal, and that they wanted to look at the contract more closely,” the paper quoted People’s Party parliamentarian Thomas Hurter as saying.
“They complained that the draft contract was only in English.”
Hurter sits in the security commission of the larger house of parliament, the National Council.
The deal will now go to the National Council for further debate in June.
There Defence Minister Maurer is expected to meet with even more opposition to his armaments programme.
“I am convinced that the National Council will want to examine this business more closely,” Hurter said.
“After all, this aircraft was chosen on the grounds that it was cheapest.”