Defence Minister Ueli Maurer reaffirmed his preference for the Swedish-made Gripen which he said at a conference in Bern was the best value for money.
"The plane meets technical demands, even if it isn't the most expensive aircraft on the market," said Maurer.
The Federal Council announced in November its decision to purchase 22 Gripen for an estimated 3.1 billion francs ($3.4 billion), reportedly the cheapest of three offers.
French planemaker Dassault's Rafale and the Eurofighter, produced by the EADS consortium, were the other bidders.
"The Gripen provides the best cost-performance," said Maurer, who came under pressure after excerpts of a critical Swiss air force report appeared in the press at the weekend.
The 2009 assessment, published in Le Matin Dimanche newspaper, said tests carried out the previous year had shown the Gripen's effectiveness "remains inadequate to achieve air supremacy in the face of future threats beyond 2015."
Maurer was on Tuesday backed up by Swiss air force commander, Lieutenant General Markus Gygax, who told the conference that Saab were offering a modernised model, with improved performance.
The decision to select the Gripen is to be sent to lawmakers for final approval later this year.
Dassault has reportedly made a counter-offer undercutting the current deal, prompting Saab to review its price.
Maurer said the government had asked the French company to submit "a concrete offer" which Bern would then assess.