She said it would be a peaceful protest, despite two shops being on the planned route.
The protest will meet at the basketball courts at Kuirau Park and walk up Pukuatua St, past two shops that sell synthetic cannabis products and turn on to Tutanekai St. It will end at City Focus.
There are four registered retailers in Rotorua, Wild Things and Skingraft on Pukuatua St, Rotorua Discounters on Tutanekai St and Adult World on Eruera St.
Skingraft owner Dave Young said he would warn his staff about the protest but he wasn't overly worried.
"You can't stop everything in this world," he said.
"We're just providing a safer alternative to something illegal. It's something that you can do without looking over your shoulder. Everything we sell has been approved. If these protesters think that the Ministry of Health is wrong then they should be protesting down there."
He said other pastimes, such as strip clubs, alcohol and pokie machines, did not come under as much scrutiny but could be classed as having negative social effects.
Rotorua police Senior Sergeant Brendon Keenan said there would be a police presence at the protest to ensure it stays peaceful. He said police had dealt with numerous incidents arising from synthetic cannabis use, especially among young people. There had been "constant reports" of youths trying to access the products through begging and asking people to buy it on their behalf.
"The effects on users makes them more angry and 'wired' than cannabis especially with energy drinks and it appears the legal highs have quite an addictive effect to the point it affects sleep patterns."
A Facebook page was set up on Monday in support of the Rotorua campaign - https://www.facebook.com/pages/Ban-synthetic-cannabis-in-Rotorua/1462495060646724. There is a nationwide page with more than 27,000 likes.