Healthcare workers, teachers, civil servants and bus and train drivers are among those taking part in strikes with members of 16 unions involved.
There was a strong turnout of workers around the local picket lines, despite the bitterly cold weather.
Here are some of the scenes as workers join the Province-wide show of strength.

9. Strike action
Staff from St John the Baptist's Primary School, Bunscoil Eoin Baiste and Naiscoil Na Banna on the picket line. PT03-233. Photo: Tony Hendron

10. Strike action
Teaching staff and classroom assistants pictured in the picket line at Hart Memorial Primary School. PT03-234. Photo: Tony Hendron

11. Strike action
Tea and coffee keeping strikers at Portadown Railway Station warm on Thursday. PT03-235. Photo: Tony Hendron

12. Strike action
Striking railway workers on the picket line at Portadown Railway Station. PT03-236. Photo: Tony Hendron