"The bulk of these are selling fatty hamburgers and it's almost predatory. I think it's a concern from the perspective of the long-term health of the country," she said.
"There's some evidence that when times are hard, people start going to McDonald's and getting their burgers because it's cheap."
Restaurant Brands is planning a Carl's Jr burger restaurant in every major urban centre, having opened sites in Takanini and Glen Innes.
McDonald's wants to build nine new outlets and eventually have 170 restaurants, according to development director Brett Watson.
Each new restaurant could cost $3 million to $7 million, with land costs of $1.2 million to $5 million, construction work of at least $850,000 with a further big spend on sophisticated internal fit-outs for kitchens.
Wendy's has outlined its best spots.
"We are opening stores in Palmerston North and Hamilton in the first half of this year and are keen to open in Christchurch, Whangarei, Hawkes Bay, Dunedin, New Plymouth, Wanganui and loads of other areas," the chain said.
An expansion document named six areas of Auckland, 10 North Island areas and three South Island cities, including plans for four in Christchurch alone.
Nick Hargreaves, Jones Lang's New Zealand managing director, said the business expansion was part of a natural evolution from older style owner-operated shops like the traditional fish and chip outlet, to the gradual entry of the global businesses with the chains and then their expansion.
Rachael Allison, Burger King's marketing director, denied an online report that quoted Savills saying the business would build 48 new restaurants in the next two years and said no numbers or timeframe were public.
"At the time of Burger King's acquisition by Blackstone it was mentioned that we planned to open four or five restaurants over the next few months," she said.
"While Burger King New Zealand is certainly committed to continuing our growth, beyond that short-term timeframe we have not discussed our expansion plans, and will not be making these public."
Restaurant Brands' KFC is also growing, spending $1.5 million on an expanded Wanganui restaurant in August.
"We've already transformed 53 stores in New Zealand and there are plans to update more. In fact, this New Zealand store design has been so successful that it has been accepted as the new worldwide standard for KFC," the business said.
FAST FOOD
* Wendy's: 22 new outlets.
* McDonald's: Nine new outlets.
* Burger King: Four to five new outlets.
* Carls Jr: Two opened and more to come.