The Northern Territory government could permanently de-restrict speed limits on select open roads after a year-long trial helped reduce road fatalities.

The Territory government has confirmed that open speed limits will be extended beyond February 1 this year while its Department of Transport undertakes a full review of road use trends, vehicle crash data and police enforcement data from a 12 month evidence-based trial. Speed limits were abolished along two stretches of open highway spanning 272km last year, with the trial originally capped at 12 months.

Provisional figures reveal that in the first 11 months, there were no recorded fatalities. The government argues 12 fatalities were recorded on the same patch of road between 2004 and 2013, with speed ruled out as a key factor in each incident.

"Following the commencement of the open speed trial on a 200 kilometre stretch of road from south of Barrow Creek to north of Alice Springs, and an extension of the trial section to include a 72 kilometre stretch of road on the Stuart Highway between the Ali Curung Rail Overpass to just north of Barrow Creek, the Northern Territory Department of Transport will now undertake a review of the trial to determine its success and future viability," Territory deputy Chief Minister Peter Chandler said.

Open slather: the Northern Territory government will temporarily extend an open speed trial while it collates different data. Photo: David McCowen

"The Department of Transport is also currently undertaking a road user survey to gain an understanding and assess qualitative experiences of road users and their behaviour on the trial section of the road. The trial will continue during the review period."

Despite successful results from the trial, not everyone is happy.

Open speed limits were scrapped in the Territory in 2007 and replaced with a 130km/h limit in return for an increase in Commonwealth funding. From that time until 2012, more people died on Northern Territory roads (307) than in the six years before the change (292). The Country Liberal Party promised a review of the capped speed limit ahead of the 2012 Territory election, which it won.

Elise McLay, from the Northern Territory division of the Transport Workers Union, said the government could be risking lives if it proceeded with permanently lifting speed limits.

Open slather: the Northern Territory government will temporarily extend an open speed trial while it collates different data. Photo: David McCowen

"We'll be interested to see what the results of the trial are, but the Transport Workers Union's position has always been consistent on the issue: speed kills," she said.

"Transport is the most dangerous industry in Australia … We need government action that will make our roads safer for everyone, not more dangerous."

The general manager of the Automobile Association of the Northern Territory, Edon Bell, accused the government of lacking transparency.

"The government has point blank refused to provide their reasoning behind the introduction of the trial, they're simply playing out on that election promise," he said.

"Whilst there hasn't been an incident in the trial area, the roads in the Northern Territory are officially rated three stars and less. The highways simply aren't in any position to support an open speed limit area.

"What we would ask is that the government is making a decision based on evidence-based research, they look at the full spectrum of evidence, open their books and let the general public see that evidence."

Open slather: the Northern Territory government will temporarily extend an open speed trial while it collates different data. Photo: David McCowen