A 36-year-old man has been arrested after an estimated $1 million worth of cannabis was found concealed in his truck.

An estimated $1 million worth of cannabis displayed here on a police car. (NSW Police)

Police stopped a vehicle on the Pacific Highway at Bangalow, near Byron Bay on the NSW north coast this morning where the male driver was submitted to a roadside drug test.

The man, from Marrickville in Sydney's inner west, was arrested after his test allegedly returned a positive indication, NSW Police said.

His truck was then searched, revealing 145 bags of cannabis with an estimated potential street value of $1 million. Methylamphetamine was also found.

The driver has been charged with supply a commercial quantity of a prohibited drug, two counts of drug possession (one being a commercial quantity) and driving under the influence of a prohibited drug.