Image: YLE

The walkout would begin on Tuesday afternoon, November 30.

The union's 2,000 members have been working without a contract since May 1. The SLSY says employers are continuously trying to undermine work conditions.

Finnair says that if the strike goes ahead it would ground most of its flights. Blue1 says it is too early to estimate the impact of such a walkout.

The threatened strike would not affect Finncomm or other airlines.

About three weeks ago, a number of flights were cancelled as Finnair mechanics went on strike. They agreed on a new contract on October 26.