Airport workers in Kenya have threatened to go on strike next week after their union issued a formal seven-day notice to the Kenya Civil Aviation Authority (KCAA).

According to Reuters, the Kenya Aviation Workers Union notified the aviation authority on February 9 that all unionisable employees would withdraw their labour once the notice period expires if their grievances are not addressed.

The planned strike could affect airport operations nationwide, including at Nairobi’s Jomo Kenyatta International Airport, one of Africa’s major air transport hubs, Reuters reported.

The union says its concerns include the failure by the aviation authority to conclude a collective bargaining agreement and the continued placement of employees on temporary contracts for positions it says should be permanent.

It is not yet clear how many workers would participate in the strike. The Kenya Civil Aviation Authority said it would issue a statement at a later stage, according to Reuters.

If the strike proceeds, it could disrupt passenger services and flight operations across the country’s airports.