"He's had his time, it's over now," Mr Norris says flatly before pointing a .223 rifle out of the LandCruiser's window and firing a single hollow-point round into the animal's skull.

It drops silently in the distance.

One consequence of the drought gripping much of eastern Australia is that kangaroos are moving across the landscape in greater numbers looking for food and water.

Many are heading into regional towns to graze on lawns leading to a spike in the number of serious car crashes they're involved in.

Highways crisscrossing NSW and Queensland are littered with dead kangaroos but the animals can also be deadly for motorists who swerve to avoid them.

"They're moving down from up north," Mr Norris told AAP this week near Deniliquin in NSW's Riverina region.

"They're moving to the roads and causing a lot of insurance claims and it's not going to get any better until it starts raining."

Mr Norris was a shearer before he took over his brother-in-law's "roo shooting" business two decades ago. He sells the marsupials to an abattoir that turns them into pet food.

After shooting the roo he clears the rifle's chamber and places it back in its holder.

"The gun never leaves the car on a shoot," he says.

The 4WD then crawls across the dusty paddock to the dropped buck.

Mr Norris steps out, opens the animal's chest with a flick of a hunting knife and stabs its heart. That's "the quickest certain death", he says, before reaching for a massive pair of bolt cutters.

Within 60 seconds the roo is butchered and hanging from a hook on his truck ready to be tagged.

He's killed 40,000 roos with this rifle and an unknown number throughout his career.

"It's just a job," he says pointing to his $300 registration sticker on the side of the ute.

Kangaroo numbers are so severe in some parts of NSW farmers are now able to apply for a shooting license over the phone and multiple shooters can operate on the one licence.

They don't have to tag carcasses but can "shoot and let lie", an Office of Environment and Heritage spokesman told AAP.

"Kangaroos move across the landscape in search of food and water," the spokesman said.

"In drier periods, when resources are scarce, they will range more widely. Unfortunately, those unable to find reliable food and water will perish."

Mr Norris says relaxing the legislation means untrained and less-skilled marksmen are now taking aim.

He's found animals with bullet holes in "the big bits" - their chests, stomachs and legs - which means they're more likely to have suffered.

"If we present a roo to the meatworks that's been shot below the neck it gets pulled aside and we get a $300 fine," Mr Norris says.

"But the farmer seems to shoot wherever he wants."

Tony Jarvis of Riverina Panels in Deniliquin says kangaroos are coming further into town to feed as paddocks and roadsides dry out.

Four of the five cars in his panel beating workshop when AAP chats to him are there for kangaroo strikes.

"It seems all we do for a living is roo damage - there's definitely more on the road now," Mr Jarvis said this week.

The kangaroos can weigh up to 60 kilograms and, Mr Jarvis explains, their heavy tails often whip around the car and strike the door after they're hit.

It's not uncommon that a bumper, headlights, radiator and door all need to be replaced.

The NSW government says it "encourages commercial harvesting as the most efficient method of controlling kangaroo numbers".

Australian Associated Press