Police in Hamilton and local health authorities have joined forces to tell dairy owners selling synthetic cannabis about the harmful effects the drugs have on people and the community.
Operation Dairy was launched in the city on Tuesday.
In a pilot before the start of a city-wide operation, 20 Hamilton East dairies and superettes were visited and 13 voluntarily agreed to stop selling K2 products.
Shops taking part in the campaign are displaying signs stating that they choose not to support the sale of synthetic cannabinoids.
Constable Briar Hallam says the response from dairies has been mixed.
"I think a lot of the dairies that do sell it chose to because of the profit margin they are making.
"They think because it is legal that they can and we are trying to convince them otherwise - but then at the end of the day if they choose to sell it, that's their choice."
Mr Hallam says shops declining to sell the drug should be applauded, while those continuing to prey on the vulnerable should be identified.