A Swiss cost-of-living demonstration called by unions and leftist parties, seeking wage rises and pension hikes, drew thousands to central Bern on Saturday a month out from parliamentary polls.

Organisers put the turnout at some 20,000, as ralliers marched on parliament to press popular demands for "better salaries and better pensions."

"Today's large demonstration sends a clear message -- in a rich country such as Switzerland there is enough money for everybody to live well," the organisers said in a statement, also urging the government to reduce recently soaring national insurance contributions.

"To save the banks they easily find billions. And during that time people have to tighten their belts. Things can't go on like that," the USS Main Union Federation said.

The soaring cost of living is a major topic along with immigration and climate change ahead of the October 21 polls with an 187 percent rise in electricity prices a particular gripe.