Sydney - The wine snobs who said Australians would never forsake bottles with corks for screw-topped ones have been proved wrong.

More than 70 per cent of this year's vintage will go on sale in bottles with metal caps. In fact, corks are now most prevalent in the cheap end of the market rather than in top-shelf wines.

To blunt the shift to metal, Portugal's Amorim has gone on the offensive, saying corks are the more environmentally sound solution because screw tops require four times more greenhouse gases to produce than corks do.

The world's largest producer of corks has a million-dollar advertising campaign running that tugs at the heartstrings of Australian drinkers.

Amorim is warning that ditching corks will see the loss of Portugal's cork oaks, the animals and plants that thrive in them, as well as 60,000 jobs. The forests, according to the campaign, soak up 5 million tones of carbon dioxide emissions.

The family-owned company will be hard pressed to save its Australian market.

Ten years ago, wine enthusiasts said they would not desert the cork because of that satisfying plop as it bid goodbye to the bottle. It was all about celebration, they said.

Nowadays, though, a pop in a restaurant usually signifies the opening of a cheap bottle of plonk. Not much to celebrate there. (dpa)