Thousands of tonnes of toxic waste currently stored in Sydney will be exported because Australia can't safely dispose of the hazardous material.

Federal Minister for Environment Protection Peter Garrett, in whose Sydney electorate the waste is currently stored, has welcomed the move that has outraged environmentalists.

"Australia does not have the facilities to safely dispose of the significant stockpile of HCB (Hexachlorobenzene) legacy waste," a spokesman for Mr Garrett said in a statement.

"It would take many years to develop suitable facilities...The Danish EPA (Environment Protection Authority) has agreed with this conclusion and consented to process the applications."

Australia's publicly-listed Orica Limited announced on Wednesday that Denmark had accepted its request to ship 6100 tonnes of HCB from Sydney's Botany storage facility.

Some 16,000 tonnes of HCB were created from the production of plastics and dry-cleaning materials up until 1991.

The chemical is considered a human carcinogen and is globally banned.

Environmental concerns

Orica's application has met with widespread objection from international environmental groups, including Greenpeace Australia Pacific, The Wilderness Society and the Danish Society for Nature Conservation.

"Exporting the toxic waste flies in face of international conventions to which Australia is a signatory, as well as our moral obligation to deal with the toxic waste here and not dump it in Denmark's backyard," Australia's community-based National Toxics Network (NTN) said on its website.

Three years ago, Germany refused Orica's request to ship 22,000 tonnes of HCB for incineration, with some 15,000 German citizens signing a petition against the application.

"Under Australia's international legal obligations the HCB waste can only be exported to another OECD country under the exceptional circumstance where there is no technology available in Australia to treat and destroy the waste," NTN said.

"Orica argues there is no capacity in Australia to treat the HCB waste, however waste experts and NTN agree that Australia does have the technical capacity to safely deal with the hazardous waste."

But Orica spokesman John Fetter said that planning alone would take more than a decade for such a waste disposal plant in Australia, which would then "very quickly" become redundant.

"Orica has tried on numerous occasions to set up a plant in Australia," Mr Fetter said. "There is no other waste in Australia to treat at such a plant."

Already some $15 million has been spent on a purpose-built repackaging facility for the waste, the majority of which is contaminated construction rubble, Mr Fetter said.

Transport arrangements

Mr Garrett's spokesman said export of the hazardous waste can now be considered under the Basel Convention on the Control of Transboundary Movements of Hazardous Waste and their Disposal.

For the export to go ahead, the Danish EPA must grant an import permit, before the Australian government considers granting Orica an export permit.

Mr Fetter said the process would ideally be completed to enable exports to begin late in 2010.

"The permit only lasts for 12 months and is not for the complete amount we have stored," he said.

"There will be subsequent applications for subsequent amounts in future years."

Danish environment minister Karen Ellemann said her country had to act because of treaty obligations. The shipment and treatment of the waste will also result in a major contract for a Danish company, estimated to be worth some 50 million kroner ($A9.54 million).