The Geneva branch of the Public Service Union (SSP) announced the news on Sunday, saying that talks aiming to renegotiate a collective workers' agreement had broken down.
Workers at the airport are demanding an increase in salary, saying they labour “365 days a year, at all hours of the day and night, in extreme climatic conditions, carrying heavy loads”, said SSP in a statement.
“Salaries are indecent for one of the most expensive cities in the world,” it said.
Swissport has rejected the call to increase pay, saying in a statement obtained by news agencies that the current collective agreement is valid until 2019.
Any strike would therefore be illegal, it said.
However SSP said strike action was “imminent”.
“For operational reasons information will only be given two hours before.”