The January 2020 fire tore through about 80 per cent of the Namadgi National Park after it was ignited by a defence helicopter during a reconnaissance exercise.

The fire burnt across the territory for one month and it led to the Clear Range fire across the border that left numerous properties destroyed.

Chief Coroner Lorraine Walker in January ruled against the nine Bumbalong residents, who were impacted by the Clear Range Fire, from appearing in the inquiry after they requested for one to be held.

The residents' application was based on a section of the Coroners Act that allows the granting of leave to a party if a coroner views that they have a sufficient interest in an inquiry.

They argued that "it is accepted by everyone that the Orroral Valley Fire morphed into the Clear Range Fire" and therefore the latter fire damaging property outside the ACT was legally irrelevant.

In refusing the application, Ms Walker said the Act did not allow her to inquire about incidents outside the territory, with death-related matters excepted, and that she was not satisfied the residents had a sufficient interest.

The residents' lawyers filed an originating claim in the ACT Supreme Court for review and the matter was heard in March.

The grounds were jurisdictional error, improper exercise of power and error of law.

Barrister Wayne Sharwood, acting for the plaintiffs, argued that the jurisdictional physical constraints were an inappropriate factor to consider in relation to sufficient interest.

Mr Sharwood said the relevant section of the Act imposes no geographical restrictions as to who is entitled to be granted leave.

Houda Younan SC, representing the Coroner's Court, said the plaintiffs' argument that it was irrelevant to consider geographical limitation was without substantiation.

Ms Younan argued that the Chief Coroner's approach had no error.

Chief Justice Lucy McCallum on Wednesday ruled in favour of the residents, saying she found jurisdictional error.

She said that the problem was the damage's geographical location imposing a constraint on Ms Walker's authority.

READ MORE: Fire inquiry suppresses defence names after social media trolling raised

"The misconception lies in the fact that the subject matter of the inquiry is 'the cause and origin' of the fire that was ignited within the ACT," Chief Justice McCallum said.

"The Chief Coroner has authority to inquire into that matter regardless of whether the damage caused by the fire reached over the border.

"Indeed, as recorded in her Honour's judgment, the decision to hold an inquiry appears to have been reached in response to the request by the plaintiffs in their capacity as owners or occupiers of destroyed or damaged property, even though it was understood that the property was located in NSW."

She said she was satisfied that the Chief Coroner mistook her jurisdiction in "that she considered herself to be constrained, as a matter of power, to disregard damage to property outside NSW in determining whether the plaintiffs had a sufficient interest".

IN OTHER NEWS:

Following her finding of the jurisdictional error, the Chief Justice was not required to consider the other two grounds for review.

The matter will go back to the Coroner's Court to determine - based on the Supreme Court's reasoning - the residents' application to take part in the inquiry.

Ms Walker last July announced the inquiry, which will focus on the 45 minutes it took for the helicopter crew to alert the ACT Emergency Service Agency to the fire's location.

After the decision on Wednesday, solicitor for the Bumbalong residents Sam Tierney, of Ken Cush & Associates, said the "residents are relieved that the Supreme Court has found there is no geographical limit barring them from taking part" in "the catastrophic Orroral Valley fire".

"The Bumbalong residents are grateful to the Chief Justice for hearing and determining their matter so quickly," Mr Tierney said.

The inquiry was initially set for mid July but has been rescheduled for November.

We've made it a whole lot easier for you to have your say. Our new comment platform requires only one log-in to access articles and to join the discussion on The Canberra Times website. Find out how to register so you can enjoy civil, friendly and engaging discussions. See our moderation policy here.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: