Constable Lizzie Campbell, from Kapiti police, located three large cannabis plants growing in a reserve at the northern end of Manly St, Paraparaumu Beach, on Wednesday.
The plants, concealed on Department of Conservation land, were well established and in the early stages of budding.
"Cannabis plants reach their full maturity outdoors in the area at Easter weekend, when growers look to harvest and dry their crops," Detective Matt Campbell said.
"The plants begin to bud or flower in February with reduced daylight after their vegetative stage over the long days of summer.