A clean-up is under way to limit the amount of toxic digital waste produced by an increasingly wired nation.

About 70,000 tonnes of electrical goods get dumped in landfills each year, with computers and TVs posing the biggest problem.

The clean-up comes amid suggestions that "e-waste" is being illegally exported.

John MacGibbon, who has investigated the problem of junked televisions and computers, believes e-waste is being sent overseas without proper export approval to be broken down for its components.

"My gut feeling is that it is but I can't put my finger on it or prove it one way or the other," he said.

Mr MacGibbon belongs to the Computer Access NZ Trust, a not-for-profit group set up by the Ministry of Education to promote recycling of school computers.

Mr MacGibbon and trust member Laurence Zwimpfer spent months investigating e-waste.

Their report included a copy of an email, sent to recyclers, from an agent asking for waste for export to China.

"Due to low labour cost, our well trained workers are able to manually dismantle those electrical and electronic products at lower costs than New Zealand workers do," it said.

An Auckland man told the Herald he sent "scrap metal" to China but knew nothing about exports of electronic goods such as computers.

But the man left his contact details at a used-computer business in Auckland last month.

"He said he wanted to buy all our scrap and send it off overseas," said The Ark owner Cory Dyer, whose company recycles and refurbishes computers for resale.

Trashed technology exported to poor countries has hit the headlines in recent years with pictures of children scavenging amid mountains of electronic waste from rich nations.

A big environmental nasty in computer monitors and televisions is the CRT, or cathode ray tube, which displays the software or picture.

Containing lead, mercury, arsenic and other toxic materials, CRTs have been described as "toxic time bombs" that will leach contaminants into the environment for decades to come.

Export of e-waste is illegal without a permit under the Basel Convention, which governs international transport of hazardous waste and which New Zealand signed up to in 1994.

It is policed by the Ministry for Economic Development (MED) and Customs. An MED spokesman said that "on very few occasions" the ministry had been given details of "possible exporting of e-waste without the proper authority" but information provided was "not specific" enough for the ministry to take action.

Customs spokesman Mike Wotherspoon said there was "no direct evidence" of illegal shipments.

The big fight-back against dumping of electronic products around the world has been "producer responsibility" schemes. Countries such as Sweden have been doing it for years but New Zealand's Ministry for the Environment held its first industry meeting to discuss the issue this week.

The response from big digital players including IBM, Dell and Sharp was "positive", said spokesman Steve Dixon, but he agreed the devil would be in the detail, particularly who pays - the consumer or producer.

Kiwis own around 10 million TVs and computers with half a million already discarded. Next month, in a first for New Zealand, computer company Dell, supported by the Environment Minister and Wellington recycler Remarkit Solutions, is holding an open day for people to drop off old computers, printers, scanners and ink cartridges at Wellington's Westpac Stadium carpark.

Remarkit is applying for the first-ever Basel permit to send computer monitors to Melbourne-based MRI where the lead is extracted for use as a fluxing agent in smelting.

More than 75 per cent of New Zealand homes have a computer, compared to 15 per cent five years ago.