Pilots went on strike on Friday in a wage dispute, grounding around 70% of the airline's flights and hitting some 170,000 people over the weekend.

"We deeply regret that our customers are affected by the ongoing pilot strike," SAS said in a statement.

Some 64,000 passengers will be hit on Sunday as 587 flights are cancelled.

'Real will'

"We believe the unions have to face reality and resume talks," Torbjoern Lothe at the Norwegian Confederation of Enterprise, an employers' association involved in the negotiations with the unions last week, told Reuters.

One of two SAS pilot unions in Norway, Norsk Pilotforbund, said it had had no contact with the airline.

And Rawaz Nermany, chairman of the Swedish Airline Pilots Association, said: "We are waiting for SAS to get in touch and show a real will to discuss the issues that are important to us."

Pilots in Norway, Sweden and Denmark went on strike.

A total of 670 flights were cancelled on Friday, affecting 72,000 passengers, SAS has said. And cancellations on Saturday affected 34,000 more people.

The pilot walkout comes after negotiations over pay and work schedules - which began last month - broke down.

Most domestic, European and all long-haul flights have been cancelled. The strike does not affect flights operated by SAS partners, which make up approximately 30% of all departures.

Customers who have a flight booked, are advised to check if their flight is affected by the strike.

'Negative consequences'

SAS has said it wants to "reach an agreement to end the strike as soon as possible", but warns if the pilots' requirements were met it would have "very negative consequences" for the airline.

Pilots are trying to secure a 13% wage increase. They currently earn an average of 93,000 Swedish crowns (£7,500) a month.

The pilots' walkout comes against a backdrop of tough business conditions for SAS. It is currently in the middle of renewing its aging plane fleet and faces rising competition from budget carriers such as Norwegian, Ryanair and Easyjet.

The airline reported a bigger-than-expected loss for its first quarter in February, but said it still expected to record a profit for the year.