More than 8,700 days were lost to industrial disputes in the second quarter of 2015, according to new figures from the Central Statistics Office (CSO).
This compares with 8,014 days during the same period last year.
The latest figures show some 8,792 days were lost on account of three disputes involving 10,100 workers.
Disputes in the transportation and storage sector accounted for 65 per cent of all days lost during the second quarter
Disputes in the education sector accounted for 98 per cent of all days lost during the first quarter of 2015, as industrial action undertaken by unions late last year continued.
More than 24,000 days were lost on account of four disputes involving 27,588 workers in the first three months of the year.
The number of days lost in the first quarter was higher than for the whole of 2010, 2011 and 2012 combined, according to the CSO.