"It's about how do we create an experience for our customers that everyone can take part in because regardless of whatever your challenges may be in life we all deserve the same opportunities."
The initiative in Trafalgar Square originated from staff member Theo Hogg, previously from Countdown Marton, whose son is severely autistic.
The quiet hour got positive feedback in Marton, so Dinnan - who was the previous store manager of Marton Countdown - wanted to bring it to Whanganui.
She said so far the response from customers has been great.
"A lot of the elderly really love it because it's not just around autism, it's around any need so a lot of the elderly really love it, it's just a nice atmosphere even for the team as well."
Dinnan said it has been a good opportunity to create a judgment-free zone to increase awareness and an understanding of the needs in the community.
Auckland City Metro and Cable Car Lane would be the only two stores nationwide not offering a quiet hour.