Switzerland cannot defend itself against a full-scale attack and must boost military spending given rising risks from Russia, the head of its armed forces said.

The country is prepared for attacks by "non-state actors" on critical infrastructure and for cyber attacks, but its military still faces major equipment gaps, Thomas Suessli told the NZZ newspaper.

"What we cannot do is defend against threats from a distance or even a full-scale attack on our country," said Suessli, who is stepping down at the end of the year.

"It's burdensome to know that in a real emergency, only a third of all soldiers would be fully equipped," he said in an interview published on Saturday.

Switzerland is increasing defence spending, modernising artillery and ground systems and replacing ageing fighter jets with Lockheed Martin F-35As.

But the plan faces cost overruns, while critics question spending on artillery and munitions amid tight federal finances.

Suessli said attitudes towards the military had not shifted despite the war in Ukraine and Russian efforts to destabilise Europe.

He blamed Switzerland's distance from the conflict, its lack of recent war experience and the false belief that neutrality offered protection.

"But that's historically inaccurate. There are several neutral countries that were unarmed and were drawn into war. Neutrality only has value if it can be defended with weapons," he said.

Switzerland has pledged to gradually raise defence spending to about 1% of GDP by around 2032, up from roughly 0.7% now – far below the 5% level agreed by NATO countries.

At that pace, the Swiss military would only be fully ready by around 2050.

"That is too long given the threat," Suessli said.