Doctors are calling on the NT government to abandon an open speed limit trial, saying it will cause more deaths on the roads.
A trial along a 200km stretch of the Stuart Highway between Alice Springs and Barrow Creek is due to begin on February 1, but doctors say it's politically motivated and will cause more deaths.
Per capita, NT roads are responsible for more road fatalities and major injuries than any other state or territory, they say.
Four major medical groups representing more than 50,000 medical professionals across Australia sent an open letter to the NT government on Friday asking it to cancel the trial, citing an irrefutable link between high speed limits and increased crashes and fatalities.
"Speeding kills," Dr Christine Connors, of the Royal Australasian College of Physicians, told reporters in Darwin.
"If we're driving very fast and something happens, by the time we've reacted we've travelled a fair distance, by the time we brake, we've travelled even further, and when we hit something at high speed the impact is much greater," she said.
"We'll end up with more severe injuries and more deaths."
Emergency physician Dr James Fordyce said there wasn't much that seatbelts and airbags could do at high speeds.
"The brain is going to bash against the front of the skull, major organs in the chest will be torn," he said.
"(The trial) appears to me to be a decision that's more based in politics than research."
The government has commissioned four reports into open speed limits but the doctors say it has declined to release its findings.
Evidence shows that when highway speed limits are increased there is also a spike in speeding on other roads, said Dr Robert Parker, vice-president of the Australian Medical Association NT.
"If they're driving quickly on main roads, they'll drive quickly on other roads, too; it's just human behaviour," he said.
He dismissed the argument that driving faster can help alleviate driver fatigue.
Between 2001-2011, there were no speed-related fatalities on the proposed stretch of road for the trial, Transport Minister Peter Styles has said.
There was an almost 25 per cent drop in road fatalities in 2013 compared with 2012, Chief Minister Adam Giles said.
Meanwhile, the government says from February 1, fines for speeding will go up to $1000 in some cases.