Increasing numbers of workers are now tied to jobs in which their employer is under no obligation to provide work, Radio New Zealand reports.
Unions are warning the shift toward such insecure work is creating an impossible situation for people trying to make a living.
Unions say New Zealand firms are now following their counterparts overseas and adopting what are called 'zero hour contracts', where workers have to be available for work, but have no hours guaranteed.
Brett Patterson works for Burger King in Hamilton and is one of thousands of employees in the fast food industry on zero hour contracts. While he works most weeks, he says it's hard to make a living.
“Because we've got zero hours in our contract - like never guaranteed - I find myself always trying to fight for the hours. It's hard when you get sick, because when you get sick you can't be there as much to fight for the hours.”
The Unite Union represents fast food workers. National director Mike Treen says zero hour contracts are now the norm in the industry.
“McDonald's, KFC, Pizza Hut, Starbucks, Burger King, Wendy's - all of the contracts have no minimum hours, and so people can be - and are - rostered anywhere from three to 40 hours a week, or sometimes 60 hours a week, and it depends a lot on how you get on with your manager.”
The fast food operators did not return Radio New Zealand's calls or declined to comment.