Families of the victims of a fire at a Swiss bar on New Year's Eve have expressed shock after officials admitted the venue had not undergone safety checks for five years.

Romain Jordan, who represents some of the families, stated the staggering number of breaches and shortcomings in the inspections raises the question of whether the municipality should be investigated with even greater urgency.

Other lawyers are urging officials to take responsibility for the disaster at Le Constellation bar in Crans-Montana, where 40 people died and 116 were injured.

Prosecutors believe the fire started when champagne bottles with sparklers attached set light to sound-insulating foam on the ceiling.

The two bar managers have been placed under criminal investigation, although they are not in custody.

French couple Jacques and Jessica Moretti are suspected of manslaughter by negligence, bodily harm by negligence, and arson by negligence. In their initial statement since the fire, they expressed being devastated and pledged full co-operation with the investigation.

According to local regulations, venues like Le Constellation should have been checked annually; however, Mayor Nicolas Feraud admitted he could not explain the lapse in inspections. We regret that - we owe it to the families and we will accept the responsibility, he said.

The mayor also announced that sparklers would now be banned in local venues.

Most victims of the fire were young, with eight under the age of 16. Many of the injured are receiving treatment for severe burns in Switzerland and other European countries, while funerals for some victims are already underway.