"The country is in a good position, this will upset the country, it's shocking."
Administrator Leeanne Clayton, 54, said she thought he must have had enough.
"He's been honest and upfront to New Zealand and if that's what he wants to do, good on him. He hasn't really had a life for the last eight years so if he feels he has nothing left in the tank, fair enough. It's like any one of us, if we've had enough in a job then it's time to go," she said.
Beneficiary George Moengaroa, 47, said it was shocking and he wondered why.
"I think it's a bit bizarre, it's unusual really. I don't think it's right, there must be something wrong."
Bank teller Amber Purcell, 25, said it was a big surprise.
"I don't normally follow politics that much but I don't understand why someone would stand down if they have gone through the effort to get there."
Starbucks Rotorua manager Cathi Brown said she was a bit disappointed.
"Because he's not seeing out his term, I don't mind him, but I think any Prime Minister needs more than one term to achieve what they want to get done. I'd like to know why," she said.
Retailer Renee Low, 23, said she thought it was "choice, he's been awesome, but not that awesome. It will be a good chance for somebody else to make improvements".
However, local health manager Donna Blair, 39, said she liked some of the strategies Mr Key had put in place.
"Since he has been Prime Minister there's been targeted funding specifically to help people with meth addiction. I'd quite like to see that continue regardless who is in," she said.
Banker Kama Aldworth, 38, said she wondered who was going to run the country next.
"It's interesting, it's a bit of a surprise, I'm not sure what to say."
Early childhood teacher Haylee Moree, 44, was surprised.
"Wow, I didn't realise. I think it's sad, I think he's been doing a great job. It will be interesting to see who is taking over him."