Unite Union says Restaurant Brands has agreed to do away with zero hours contracts.
The union's national director, Mike Treen, said it meant workers at KFC, Pizza Hutt, Carl's Junior and Starbucks will have guaranteed hours giving them job stability.
He says there were also strict clauses in the agreement that if a worker leaves, or if more shifts become available, they'll be offered to existing staff first.
Unite has 2000 members at the chain and is recommending the new terms to members in a vote to be held over the next week or so.
"This is a gigantic step forward for workers in the fast food industry" Treen said.
"It is time for New Zealanders to tell these profitable multi-national chains that they need to stop taking advantage of their often young and vulnerable workers and put an end to a labour practice that the people of New Zealand have made clear they find unacceptable."
Treen said Restaurant Brands will end zero hours contracts by July - now he wants McDonald's, Burger King and Wendy's to follow suit.
Company chief executive Russel Creedy told Radio New Zealand's Morning Report show this morning that when the union approached the company about providing better certainty over working hours, he immediately saw change was needed.
"Having permanent staff who stay with us, loyal, long tenure, is part of a successful business model for our industry," he said.
Creedy said the company had never really practised zero hour contracts, and this change provided better security for both workers and company.
"It's no secret that in our industry we employ a fair number of students, and unfortunately all the universities have student exams at the same time," he told Morning Report.
"So there's generally a bit of an exodus of hours worked around exam times and that is problematic for us, because the students are not always available.
"So getting greater security for availability is important and valuable to us."