Six of the 12 sections of Central Australia's prized 230-kilometre Larapinta Trail, near Alice Springs, have been closed due to a bushfire in Tjoritja (West MacDonnell) National Park.

Northern Territory Parks and Wildlife district manager Phil Cowan said the fire has been burning for more than two weeks.

Mr Cowan said the fire was believed to have started on nearby pastoral leases and spread to the national park.

He said no assets were at risk however the parks remain closed until further notice as a precaution.

"We've got section six to 11 still closed on the Larapinta Trail and Ormiston Gorge remains closed," Mr Cowan said.

"So no camping or day visitors are able to get into Ellery until we reopen."

Serpentine Gorge, Serpentine Chalet and the Ochre Pits along Namatjira Drive also remain closed.

Water-bombing capacity

Mr Cowan, who has seen the efficacy of water bombing in other states, said there was no capacity for that firefighting method in Alice Springs.

"There is in the Northern Territory, but not in Alice Springs ... It's very expensive to get resources down from Katherine and Darwin to be able to do that," he said.

"It is difficult. You've got to have access to water close by."

He said water bombing was more effective on smaller contained fires rather than on a wildfire front.

"The hot weather and the really low humidity has just not been very helpful to us at the moment."

Assessments are underway 

Mr Cowan said the landscape was difficult to reach given its isolation and terrain.

"In those valleys with all the last two years of rain we've had over summer has really fuelled that grass growth and that's what's burning at the moment," he said.

He said using the terrain at Ellery Creek Big Hole to mitigate the fire was an option.

"We're hoping to pull [the fire up] around there."

People are being urged to check the Northern Territory Parks and Wildlife for updates on closures.