Kenya's Workers Aviation Union (KAWU) said that it will go on strike from next Monday over plans to lease Jomo Kenyatta International Airport to a private operator.
The industrial action would likely cause significant disruption to national carrier, Kenya Airways, and operations at the airport which is a key African travel hub.
KAWU, which represents airport workers, said the proposed deal announced last month with India's Adani Airport Holdings would result in job losses.
It has called on the government to scrap the deal which is sees as the "unlawful intended sale" of the airport.
The government, however, said the airport was not for sale and that it had not decided whether go ahead with what it described as a "public-private partnership" to upgrade the hub.
Kenya's Airports Authority said the investment proposal includes a second runway and upgrades to the passenger terminal.
It hopes that a resolution with the union can reached through negotiation.
