Numerous KFC, Pizza Hut and Carl's Jr fast food outlets around New Zealand were closed or short-staffed this weekend after many workers went on strike.
It was the second strike in six months against franchisee Restaurant Brands over pay issues.
United Union Lead Secretary Gerard Hehir said employees were "furious" with Restaurant Brands for trying to enforce what he called "dangerous policies" that were "detrimental" to staff well being.
Hehir said Restaurant Brands wanted to cut paid 15-minute breaks to only 10 minutes.
The response of union members to that was "hell no", he said.
Hornby Pizza Hut Manager Cheyenne Parris said the shorter breaks were "ridiculous".
"I'm not happy about it."
New Brighton Pizza Hut duty manager Otis Singleton felt differently, saying 15-minute breaks were difficult when there was not enough staff to help out.
"It doesn't bother me. They [breaks] are a pain to give out especially when the store is busy."
Hehir said Restaurant Brands was also planning to cut overtime pay for employees, who worked more than 50 hours a week.
The franchisee made 39 million dollars in profit last year, he said.
Negotiations between Unite Union and Restaurant Brands is ongoing.