Some 400 Swedish SAS pilots walked off the job on Friday in a dispute over wages and working conditions, stranding 4,000 passengers, the Scandinavian carrier said.

"The Swedish pilots union has called 400 members on short-haul flights out on strike. Both domestic and European flights from Sweden are cancelled," the company said in a statement.

Some 40 flights flown by pilots based at Stockholm's Arlanda airport were cancelled after the strike broke out at 6:00 pm (1600 GMT), SAS said. 

After months of negotiations, the Swedish pilots union SPF rejected the mediators' proposal of a 2.2 percent wage increase, insisting on a 3.5 percent increase.

The employers' organisation insisted however that the pilots' overall demands, including employment contracts offering greater job security, would entail a 10 percent cost increase.

"We want our employees to feel secure in their jobs, but the pilots' wage demands are just too high. We can't afford to pay that much given the competitive (air travel) market," SAS chief executive Rickard Gustafson said Friday before the strike broke out.