Wendy's staff may turn to industrial action if negotiations over lieu days break down.
The move follows Lyttelton port workers striking over wages and rosters, and nurses saying strike action is likely after they rejected a pay offer from district health boards.
The fast food workers' move comes after a three-year battle over lieu days, prompted by Hornby Wendy's staff member Rose Williams.
She went to the Ministry of Business, Innovation and Employment with the lieu day issue after she had been working at the Hornby restaurant for a year.
Williams said Wendy's staff were not being given a lieu day after working on a public holiday.
In November, the Employment Relations Authority ruled in favour of Williams and Wendy's was found to have breached two sections of the Holidays Act 2003.
Wendy's was given a list of orders including giving past and present employees their days in lieu or equivalent pay dating back to July 1, 2012, or since the restaurants had opened.
Unite Union, of which Williams is a delegate, has estimated it would cost Wendy's $1.6 million to pay back employees' lieu days.
The union's national director Mike Treen said it has sent a final terms of settlement to the fast food company.
"If no final agreement can be achieved very soon, we will be forced to ask members to take industrial action in support of our claims," he said.
But Treen said it might not come to that as he doesn't know what Wendy's "final position" is.
"I don't even know if there's a problem with lieu days at Wendy's actually because they haven't come back," he said.
Wendy's did not respond to questions from Western News.
- The Star