Cyber-environmentalists said Thursday they aim to mobilise millions of people around the world for a mass waste clean-up, saying they had to step in because governments had failed to do so.

Tiina Urm, spokeswoman of the Estonian-piloted "Let's Do It!" campaign, told AFP that anti-waste activists hoped to see numbers spiral this year thanks to projects in 82 countries, five times more than in the successful 2011 edition.

"By the end of 2011 more than 2.7 million people have participated in Lets Do It! cleanup actions in 16 countries. We hope that this year's global campaign will attract tens of millions, and our most positive expectation is to reach 100 million," Urm said.

The campaign started in 2008 in Estonia, where organisers created special software to map and photograph 11,000 illegal garbage dumps across the nation of 1.3 million people.

A total of 50,000 volunteers mustered by the campaign's website managed to locate and collect 10,000 tonnes of illegally dumped trash in one day, leading organisers to go global.

The 2012 edition, running from March to September, aims to gather hundreds of thousands of tonnes worldwide.

Team leaders from 46 countries gathered in the Estonian capital Tallinn on Thursday for a four-day conference focusing on the 2012 campaign.

"Despite all the talk, climate conferences and political efforts in last 20 years, the world's getting dirtier," campaign chief Rainer Nolvak told AFP.

"Governments have demonstrated that they cannot reverse this," he said.

"So we are going to clean up the planet, together with communities around the world... Why create waste at all? Humans are the only species on Earth who does that," he added.

Among the countries involved in the 2012 campaign is Estonia's giant neighbour Russia.

"Waste is becoming an important issue in Russia, not only as a problem for government and society to discuss and solve, but also as something that encourages people to unite and make them to do something on their own initiative," Russian campaign organiser Tatyana Kargina told AFP in Tallinn.