NAIROBI (AFP) -- The United Nations has pressed for a watertight framework to save developing nations from unregulated imports of electronic wastes that release heavy metals and chemicals.

A day before experts from 120 countries gather in Kenya for a global hazardous waste conference, the UN Environment Program (UNEP) said between 20 to 50 million metric tons of electronic wastes are generated annually in the world.

With some computers, cell phones and other gadgets going out of use within months of production, so-called e-waste is considered the fastest growing part of municipal waste in the developed world.

Most of it is shipped to the poor world, mainly Africa, under "refurbished" banner and end up in junkyards where the goods rot and release lead, canadium, mercury and other deadly compounds that pollute the environment.

In the absence of reliable figures, experts speculate that anywhere between 25 to 75 percent of the e-waste that enters Africa -- mostly through Mombasa, Lagos and Dar es Salaam ports -- is useless.

In Nigeria, about 500 containers full of used electronic cargo pass through the Lagos port every month, according to a recent study by Seattle-based Basel Action Network.

As the Basel Convention, which came into force in 1992 and has more than 160 state parties, comes up for review at a week-long conference here, governments are expected to adopt a framework to tighten shipments and disposal.

But the treaty's executive secretary, Sachiko Kuwabara-Yamamoto, said there was a need to raise awareness of the dangers posed by the explosion of electronic wastes.

"Because you only manage what you can measure, we need to shine a brighter light on hazardous wastes -- on where they come from and on where they end up," Kuwabara-Yamamoto said Sunday.

"More and better information about waste will also help us to tackle the growing challenge of illegal trade," she added, explaining that the 8th meeting of the conference of parties to the Basel convention will seek to stem the tide of exporting e-waste to the developing world.

Kenya's Environment Minister Kivutha Kibwana said that while Africa bore the brunt of e-waste, the entire world will have to face the aftermath of resultant pollution.

"Some of these computers, when they are coming here, they are already obsolete and so the countries do not ask the question: 'How will this computer be disposed after a very short state of life?'," he said.

"It is actually a very big problem ... some of these wastes are quite challenging to manage," Kibwana told a press conference in Nairobi.

"Waste is not only problematic to Africa (and other) developing countries, but the entire world," he warned.

This week, countries that have not yet ratified the convention and its associated provisions will be urged to come on board in order effectively to protect human health and the environment from hazardous wastes.

Unlike the United States -- which is not a member of the treaty -- the European Union has for several years now banned the export of hazardous electronic wastes to developing countries in order to help prevent the globalization of the toxic crisis.