Northern Territory Police have seized more than $550,000 worth of kava after a man was caught allegedly trying to take it to remote communities.

The 37-year-old man from New South Wales was arrested close to Maranboy, near the town of Katherine.

Police say he was carrying 294 kilograms of kava in plastic bags in his vehicle.

Duty Superintendent Louise Jorgensen says officers searched the man's car after he was stopped for a random breath test yesterday afternoon.

"He was evasive and acting suspiciously," she said.

"They said, 'where are you going what are you doing?'

"He said he was heading to Darwin and they said, 'well, you are on the wrong road'.

"Then they saw all the bags and they said, 'well, we are going to search your motor vehicle'.

"He said, 'well, it's full of kava'."

Kava is used as a ceremonial drink by many Pacific Islander communities and its use has grown in the Territory.

While the kava plant can be imported to Australia, it is illegal to supply and possess kava in the Territory.