Norway public sector workers were called out on strike on Thursday after salary negotiations broke down, affecting schools, day care centres and prisons.
Thursday's strike action is the first in three decades by public sector workers in the country.
Up to 30,000 of Norway's 600,000 state and municipal employees were taking part in the strike, according to a tally by the NTB news agency. That number was expected to increase unless the different unions can reach wage settlements with central and local governments.
According to NTB, the strike was the first in 28 years involving state employees in Norway, an oil-rich country of around 4.7 million people.
"I am disappointed and think it is a shame that an agreement could not be reached through negotiations," Administration Minister Rigmor Aasrud said in a statement.
She insisted that Norway's left-leaning government had proposed wage hikes that "would have ensured a significant purchasing power increase to all state employees," offering to increase salaries by 3.75 percent.
The different unions however had demanded that their members receive the same increase as in the private sector, which they said was nearly 4.3 percent.
"The government cuts us off with worse wage development than for employees in the private sector. That is unreasonable," Arne Johannessen, chief negotiator for the Unio union representing teachers and day care workers, said in a statement.
Some 8,500 of Unio's members were taking part in the strike, affecting schools and day care facilities across the country, except for in Oslo, where negotiations continued.
Norway's main union, LO, also criticised state and municipal governments for failing to agree to "fair demands for wage development on a par with the rest of the workforce."
"A strike could therefore not be avoided," LO chief Roar Flaathen said in a statement.
Some 10,000 of LO's members did not show up for work Thursday, affecting among others municipal administrations, traffic and harbour authorities.
Police, customs authorities and prisons were also affected, forcing for instance all prisoners at one prison to be transferred to other facilities, NTB reported.