Kenya Airways, already facing financial difficulties and a threatened pilots' strike, cancelled five flights on Sunday after outsourced cabin crew walked off the job.

While the stoppage only involved a small number of workers, it coincides with a deep malaise at the airline, which in July posted a net annual loss of 26.22 billion shillings ($250 million/230 million euros) -- the worst ever since its privatisation in 1995.

The losses follow a series of disastrous strategic decisions touching on maintenance costs, a hedge on fuel prices and rising dollar-denominated loans.

"Some of our outsourced staff including cabin crew have stayed away from work from Friday and we are working with their employer to resolve any issues they may have," Kenya Airways said in a statement on Twitter.

"As per the safety regulations that the airline abides to, minimum number of cabin staff per aircraft type is required and on some of our flights we are unable reach these levels," it said.

The dispute forced the carrier to scrap flights to the Kenyan city of Mombasa, Kilimanjaro (Tanzania), Juba (South Sudan), Maputo (Mozambique), and a further flight to Harare, Zimbabwe, via Lusaka, Zambia. No intercontinental flights were affected.

On Friday, some 700 outsourced workers employed by Career Directions Limited complained they had spent six years being retained on one-year contracts and demanded their wages be aligned with those of Kenya Airways' staff.

Kenya Airways faces a strike on Tuesday by disgruntled pilots who have for months been expressing a lack of confidence in the managerial team.

The pilots' union KALPA said last week they would stop work for a week if management did not step down. 

The airline, which later this month will release half-year results, responded by obtaining a court order to bar industrial action.

On Thursday, Transport Minister James Macharia said a strike would amount to "national sabotage."