ACC staff from Dunedin joined their peers in Auckland, Wellington and Christchurch for a second strike to oppose an "unacceptable pay offer" from the Crown entity.
PSA national secretary Fleur Fitzsimons said the ACC failed to make an offer that valued its workers and helped them keep up with the cost of living since a strike in July.
A recent PSA survey found the rising cost of living had a significant impact on ACC workers and they were looking for jobs outside the ACC with better pay.
More than 90% of ACC workers had to reduce spending on non-essential items and 78% found it hard to afford basic necessities such as food, housing and utilities.
Eighty percent felt less financially secure than they did six months ago and 37% had sought additional income by taking on a second job or taking out a loan. Three percent relied on foodbanks.
