The new look was driven by the spate of ram raids, which have been happening almost daily around the country, with Auckland and Waikato, particularly under siege.
Paroa is on the southern end of Greymouth on State Highway 6.
Ram raids are unknown on the Coast, but Birch said the rocks would offer security while also adding an authentic West Coast look.
"It is as a precaution as there are a lot of ram raids going on — it's happening everywhere," he said, adding two South Island On the Spot stores had also reportedly been hit.
"We got the rocks from Westland Schist and they look great, especially as a deterrent.
"Everyone that comes into the shop likes the idea and the look."
The couple also plan to place a number of smaller rocks to soften the look, as well as a new bench seat at the front of the store.
