An independent Member of the Northern Territory Parliament says importing radiopharmaceuticals from overseas is unsafe, unreliable and expensive.

The independent Member for Nelson, Gerry Wood, says he has been advised by the chief scientist at the Australian Nuclear Science and Technology Organisation (ANSTO) that not all nuclear medicines can be flown into Australia.

A letter from Dr Ron Cameron explains that radioactive medicines have short half-lives and often do not survive long flights intact.

Mr Wood says that proves Australia is far better off building a new reactor.

"Because of the unreliability of say the transport and the flexibility of the market, it's far better for Australia to have its own means of producing those radiopharmaceuticals and that's why we need Lucas Heights," Mr Wood said.

A national nuclear waste facility is a prerequisite for the new reactor to be granted a license.