The Federal Government has released a tender calling for concept designs for Australia's first radioactive nuclear waste dump.

The Government has previously announced its preferred site for the dump is on Muckaty Station in the Northern Territory, about 120 kilometres north of Tennant Creek.

The tender says the concept design will be appropriate for a site in arid to semi-arid areas of Australia.

It says the facility should be designed to accommodate waste for at least 100 years, and equipment at the site may be required to repackage the radioactive waste.

Nat Wasley from the Beyond Nuclear Initiative is campaigning against the dump.

Ms Wasley did not know the tender was being released.

"It came as quite a surprise, but once again it's an indication of the completely secretive and very un-transparent [sic] process that the Government's been using," she said.

Submissions for the tender close in September.