Geneva: A woman who wanted to stop her husband boarding a plane at Geneva has admitted making a false bomb threat, prosecutors said on Wednesday, after hours of tightened security that caused traffic chaos around the airport on the French-Swiss border.

"Yesterday in the evening, a woman called Swiss customs at Geneva airport. She said that today a person carrying a bomb would be in the French sector of the airport," the Geneva prosecutor's office said in a statement.

The Swiss authorities traced the number to Annecy in France, some 45 kms from Geneva, where French police raided an address.

"They found a woman who admitted to having made the call and explained that she wanted thereby to prevent her husband from leaving," the statement said.

Criminal proceedings have been opened against the woman, who was not identified, in both France and Switzerland, it said.

The hoax call caused French and Swiss police to massively scale up security at Geneva's Cointrin airport, which straddles the border.

Officers armed with machine guns were on duty around the airport, and vehicles were stopped on approach roads so that police could check people's papers, causing long tailbacks.

Most entrances to the airport were closed. Passengers were channelled through a few doors where heavily armed police again checked identity documents. But airport officials said the airport was open and functioning normally, despite the delays.

"We have received information that is serious enough to put in place preventive controls here at Geneva airport. We cannot give details of staffing numbers, nor on the information we have received, for obvious reasons of security," a Geneva canton police spokeswoman said before the alert was lifted.

Airport spokesman Bertrand Staempfli advised passengers to arrive early because of the extra checks but said there were no serious problems with access.

Security was also heightened on the French side of the border. France itself is on high alert after a series of Islamist militant attacks, including the killing on Tuesday of a Catholic priest during a church service in northern France by knife-wielding assailants.

The Tribune de Geneve paper said one of the assailants in that case was arrested at Geneva airport last year while trying to travel to Syria and was later extradited to France.