More than six million volunteers from 96 countries collected an unprecedented 100,000 tonnes of garbage last year as part of a global, web-driven clean-up campaign, cyber-environmentalists said Friday.

"Last year the most astonishing numbers of volunteers attended clean-ups in Sweden, Bulgaria and in Slovenia," Tiina Urm, spokeswoman for World Cleanup 2012 told AFP.

Nearly 700,000 Swedes, 322,000 Bulgarians and 265,000 Slovenians turned out to clear trash, often illegally dumped garbage, pinpointed with special software using Google Maps.

"In the last five years seven million volunteers have attended our clean-up actions," Urm said.

The Let's Do It! campaign started in 2008 in Estonia, where organisers created special software to map and photograph over 10,000 illegal garbage dumps across the Nordic nation of 1.3 million people.

In what proved an unexpected success, over 50,000 volunteers collected 10,000 tonnes of illegal garbage from roadsides, forests and towns in just five hours.

Backers of the clean-up campaign say the world is drowning in 100 million tonnes of illegally dumped trash.

A global cyber-environmentalist meeting to be held in Tallinn in February will focus on ways to expand the global clean-up.

Pictures, data and maps about World Cleanup 2012 are available on www.letsdoitworld.org.