Consumers are being asked to buy "true" Ontario wine as they stock up for the holiday weekend — a move grape farmers and their supporters say will help give the industry a much-needed boost.

Grape grower David Wiley says he has $500,000 worth of grapes on his vines that may not find a home because Ontario law allows wine to be labelled as "cellared in Canada" if it contains up to 70 per cent foreign grapes or grape product.

He wants labelling at the LCBO to be more clear so people understand when they're really buying local product.

Rick Smith of the group Environmental Defence says the province must to make some changes to wine regulations to help Ontario grape growers.

Smith, along with the Ontario Greenbelt Alliance, stomped grapes outside a flagship LCBO store in Toronto while urging consumers to make sure any Ontario wine they buy displays a VQA label on the bottle.

That's a marking that ensures the wine is made of 100 per cent Ontario grapes.

LCBO spokesman says the store has been doing all it can to educate consumers, noting sales of VQA wines have risen by 25 per cent.