The Northern Territory is set to house a national radioactive waste dump, after the federal coalition resolved to support government legislation.

Opposition energy spokesman Nick Minchin on Tuesday said the coalition had long recognised the need for a central repository, but when it was in government its efforts were frustrated by state Labor governments.

"It is much more sensible for waste, resulting from medical and research procedures, to be stored in a secure, specifically designated facility rather than in an ad hoc fashion in various locations across the country, as is currently the case, he said.

Labor kept an election promise by repealing the coalition's Commonwealth Radioactive Waste Management Act 2005.

It is now considering Muckaty Station, 120 kilometres north of Tennant Creek, in the Northern Territory, as the site for the facility.

The former coalition government also considered the site, after it was volunteered by its traditional owners.

Australian Conservation Foundation nuclear campaigner Dave Sweeney said the government had simply "re-badged" the coalition's policy because finding an alternative site for the dump was too hard.

The consent of all of Muckaty Station's traditional owners was still in contention, and the deal with those who had agreed to the plan was largely secret, Mr Sweeney said.

"Labor promised it would have a site selection process that was open, transparent and based on community consultation and consent," he told AAP.

"This is literally a case of out of sight, out of mind."

Meanwhile, federal parliament's public works committee is holding an inquiry into proposed extensions to the Australian Nuclear Science and Technology Organisation (ANSTO) facility at Lucas Heights, in Sydney's south.

The $62.5 million project would include a new building for the Centre for Accelerator Science, to enhance Australia's capacity for research into climate and environmental science, nuclear safeguards and forensics.

The committee will examine whether the need, cost and scope of the proposal is appropriate.