Hundreds of fast-food workers at KFC, Carl's Jr and Pizza Hut will strike this weekend.

Workers employed by Restaurant Brands and members of Unite Union voted to take strike action with 88 per cent of the 763 who took part set to down their cooking utensils.

The strike starts at 2pm today and will last until 2am on Monday morning, which includes employees from Carl's Jr and Pizza Hut.

Unite National Secretary and Lead Negotiator Gerard Hehir says wages and starting rates is the reason for strike action.

Negotiations had stretched for six days but no resolution had been reached, he said.

One of the issues of contention was how much more skilled-staff received about the starting rate for junior employees.

Hehir said the matter came to a head by the minimum wage went up to $17.70 in April.

While starting rates were raised, the same didn't take place for more senior employees, he said.

"Low wage employers need to realise that they can't get away with just increasing their lowest rate only and undervaluing their experienced and skilled staff," he said.

Restaurant Brands has been approached for comment.

The NZX-listed firm was partially taken over earlier this year in an $881m deal from Mexican fast-food investor Finaccess Capital.

Restaurant Brands' recent move to bring the Taco Bell brand to New Zealand and Australia is just one of several developments that attracted Finaccess.

Another is the steady growth Restaurant Brands has shown over the past decade with its portfolio of well-known food brands - KFC, Pizza Hut and Carl's Junior.

Restaurant Brands' shares are trading for $9.15 each.