Workers in Finland on Friday are said to be their biggest strike in over 20 years as they protest the government's new austerity measures.

At least 15 domestic flights had been canceled, while ports and public transportation were shut down.

Finnish Prime Minister Juha Sipilä has insisted that the measures—which include shortening annual holidays from 38 to 30 working days, halving overtime pay rate increases, cutting Sunday work bonuses, and reducing sick leave pay—are "indispensable" to getting the economy back on track.

"The government intends, through coercive legislation, to weaken working conditions," Lauri Lyly, leader of biggest union, SAK, said in an emailed comment to Bloomberg.

Roughly 30,000 protesters gathered in the Nordic nation's capital of Helsinki, with some carrying signs that read, "No way!"

"We all know Finland‘s economy is doing poorly," Antti Rinne, leader of the opposition Social Democrats and a former finance minister said at the Helsinki rally. "But it is not improved by forced measures but through cooperation and agreements."