Some flights will be cancelled as early as Sunday to minimise disruption, including almost all long distance flights and European flights, and all flights will be cancelled on Monday.
SLL will start a strike impacting all Finnair flights on Monday, November 16 at 0:01 am, it said in a statement.
Finnair pilots will go on strike on Monday after wage negotiations at the weekend broke down, the Finnish airline pilots association SLL said Saturday.
But the airline aims to operate all of its charter flights despite the strike.
The walkout, which will continue until an agreement between the pilots and Finnair has been reached, is expected to affect thousands of passengers. On an average day the airline serves some 20,000 customers with its 200 flights.
Finnair has been negotiating a new wage deal for a year and half, and a cost cutting programme introduced by the airline has made the discussions thornier.
On Saturday, the board of SLL discussed the wage plan drafted by national conciliator Esa Lonka, but decided to reject it because it did not provide a solution to Finnair's plans to outsource pilots.
The airline has started to outsource its flights to Finncomm airlines, a domestic carrier, and ordered its pilots to teach Finncomm's pilots.
Finnair had said it was happy with Lonka's draft proposal and was shocked that pilots had turned it down.
"We are totally stunned and apologise sincerely for the inconvenience this (strike) causes to our customers," Anssi Komulainen, head of Finnair's human resources said in a statement.
Finnair spokesman Christer Haglund told AFP that new discussions with the pilots had yet to be scheduled. He said customers with tickets on Finnair flights on Monday or later could obtain more information on the company's website.
Last month Finnair reported a net loss of 20.7 million euros in the third quarter and repeated it aimed to cut annual costs by 200 million euros.
Like the whole airline industry, Finnair has been struggling with lower passenger numbers and fares amid the global financial turmoil.