The liquor ban targets those who park up en route to the festival and drink before they go in. "Pre-loading invariably leads to incidents of disorder, fighting and assaults," he said.
Alcohol is sold at the site, but festival goers are not allowed to bring it in, and cars will be searched before entering.
A letter from Senior Sergeant Carolyn Watson in support of the ban said parking on the side of the road was hazardous in itself, and they did not want to see festival-goers drinking alcohol before heading in. "The police believe the community of Martinborough does not need to suffer any further intrusion on their peace and well-being by this potential hazard."