At least three people have died in house fires over the weekend, and 50 animals were killed in a fire at a farm on Sunday.
Several other non-fatal fires have been reported in different parts of the country, some of them resulting in serious damage to buildings.
Although in every case the cause of the fires is still being investigated, the Sonntagszeitung newspaper quoted the chairman of the Swiss Fire Brigades Association as saying there could be a serious fire risk in connection with heating problems. He cited chimneys that had not been properly swept and electric fires that had been covered over.
The Swiss News Agency said several of the fires were likely to be linked to the cold, in particular to the incorrect use of stoves.
Temperatures have remained well below zero almost everywhere in Switzerland throughout the weekend.
One person died in a fire near Martigny in canton Valais in the early hours of Saturday morning. Firemen were able to rescue a second person who was taken to hospital with smoke inhalation.
An elderly man died in a fire in Horw on Lake Lucerne, that broke out in a wooden house on Sunday morning just after midnight.
The third fatality occurred on Sunday afternoon in a block of flats in central Zurich. Another two people from the block were taken to hospital with suspected smoke inhalation.
In the village of Hinterfultigen in canton Bern 50 calves, sheep, lambs and rabbits died on Sunday morning when the stall part of a farmhouse caught fire.