An Adelaide winery is sifting through 462 cartons of damaged wine after a forklift accident destroyed $1 million worth of exports.

McLaren Vale winemaker Sparky Marquis, whose hard work went down the drain in the accident, says there was only one undamaged carton.

The cases of premium 2010 shiraz, at $185 per bottle, fell more than six metres when the forklift malfunctioned while loading the container for export at the Port Adelaide wharf on Thursday.

Mr Marquis says his staff are still sorting through the mess one bottle at a time.

"All of the bottles are in the cool store and we're just having to go through every single bottle, check it first of all to see if it has any cap seal damage to it, in which case it just gets immediately discarded," he said.

"We've got them laid out all across the winery floor, it's just a sea of cartons. Every time you move a carton, a bottle inside the carton falls apart from sheer shock and the wine just pours out."