Loss-making Finnish airline Finnair said it had cancelled some 35 flights on Tuesday due to a wildcat strike by ground handling staff.
"We have cancelled today 35 flights, which has impacted some 4,000 passengers and we have some 6,000 pieces of luggage to be delivered to their owners," Finnair spokeswoman Paeivi Huuhtanen told AFP.
"It is likely there will be more cancellations and delays tomorrow."
On Monday Finnair announced it would outsource some 490 employees at its ground handling company Northport to human resource company Barona and some 130 cargo terminal workers to Suomen Transval.
The announcement prompted around 200 employees at Northport to walk off the job on Monday. On Tuesday some of them, mainly those working at customer service, returned to work, while luggage handlers and loaders continued their protest.
The Finnish Aviation Union IAU, representing Northport employees, said the workers were worried that their transfer to Barona -- which came into effect on Tuesday -- would lead to a deterioration of their work conditions and part-time work or redundancies.
"We will negotiate with Barona tomorrow. I hope that we can reach an agreement with them," IAU chairman Juhani Haapala told AFP.
He said the strike could end on Wednesday if the negotiations with Barona were successful.
Finnair, like much of the airline industry, has struggled as passenger numbers and fares continue to plunge following the recent global financial turmoil.
The carrier has been tackling the problem by cutting routes and staff.
In the January-September period Finnair had nearly 9,000 employees, which is around 600 fewer than in the same period in 2008.
Finnair aims to cut its annual costs by 200 million euros (301 million dollars) next year and has said further personnel reductions are possible.
In the third quarter it made a net loss of 20.7 million euros.
