The threat from the airline applies to Swedish workers from the HTF union, which represents cabin crew. The union has called a strike for the 26th May.
"The lockout shows how seriously we view the situation and the consequences it would have for our customers. We expect that a lockout will accelerate a solution of the conflict," said Anders Ehrling, CEO of SAS Sweden.
"We have offered a three-year deal with a wage increase of 10.2 percent, which is the same level as the rest of the market. We have been met with counter-demands which would lead to a rise in costs of around 25 percent a year," he continued.
"We have started mediation and are focusing on supporting the mediators. We are expecting the mediators to present a proposal within a few days."