New rules aimed at improving security of radioactive materials will protect against the building of a "dirty bomb", say those charged with the case of our most toxic nuclear material.

They will see radioactive material used for cancer treatment, research and other mainly medical purposes governed by rules which insist it be transported securely or kept in secure facilities.

The steps are aimed at bringing New Zealand's rules around management of radioactive material up to an international standard set a decade ago. Led by the Ministry of Health, it comes at a time when greater focus is being applied to security at all public buildings across the country.

The type of radioactive material targeted has featured in nightmare "dirty bomb" scenarios for Western security services. While not nuclear in capability, a "dirty bomb" is one which spreads radioactive particles across a wide area.


The new rules were revealed in the ministry's call for submissions on a draft Code of Practice for the Security of Radioactive Material. The final code is expected to be in place next month and will insist on security measures in keeping with the threat level of the nuclear material they hold.

For those with "Category B" nuclear material -- the most potent in New Zealand -- they will be required to have "delay mechanisms", including "at least two barriers", which would allow those running the facility time to stop anyone trying to steal the radioactive compound.

They are obliged to have an instant alert to unauthorised entry and to "immediately respond with sufficient resources to interrupt and prevent the removal of the material". Staff wanting access to the most potent nuclear material are also facing police checks.

University of Auckland medical school Professor Bill Wilson said cancer research at the Auckland Cancer Society Research Centre was aided by a machine which used Cobalt 60 and was now captured by the proposed code.

Professor Wilson, who has been involved in world-leading cancer research, said new security measures had been taken -- including not advertising where it is -- and other measures were being considered.

He said concern over a "dirty bomb" had increased over the past decade. "The concern is the potential for a radiological bomb where a large amount of radiological material is exploded and distributed in a city. As a nuclear-free nation, the last thing we want is an incident."

The Co60 was kept in a cubic metre block of lead, which was considered reasonable protection against it being moved.

Professor Wilson said the greatest risk was during movement of material. The Co60 had a half-life of five years, meaning it reduced in potency periodically and would likely need replacing about 2028.

It was last replaced in 2013 when it was brought from "Auckland airport in the dead of night by a local courier".

"Next time it happens we're likely to see a higher level of security. If someone is going to score themselves a Cobalt 60 source, they're going to do it when it's on the hoof."

Radioactive material is able to be held only by licensed individuals, who are personally responsible for what happens to it. The code expands responsibility to the institutions at which radioactive material is held.

Ministry of Health team leader for the Office of Radiation Safety, Stuart Lillee, said the new rules brought New Zealand in line with international conventions passed in 2005, including one aimed at inhibiting nuclear terrorism. Security procedures would also be aligned with the national threat level and be scaled up if the threat to New Zealand increased.

He said those handling radioactive material had a good level of compliance but there were areas for improvement. "In particular, the ministry is looking for some entities to increase the frequency of trustworthiness checks for staff."

Intelligence analyst Paul Buchanan said the threat of a dirty bomb had long haunted Western agencies troubled that fanatical terrorists would not care about the cost of accessing the material.

"If you're intent on martyrdom, you're not going to worry about exposing yourself to radioactive poisoning." He praised the creation of the code: "I'm really glad they have this process."