Agriculture Victoria district veterinary officer Dr Jeff Cave said while it is legal to allow appropriately restrained dogs to travel on the back of utes, dogs left in the sun for long periods can quickly dehydrate or even die from heat stress.

"Adequate shelter, for example a fixed canopy, needs to be provided to protect tethered dogs from extreme temperatures," Dr Cave said.

"A lot of utes and tray backs these days are made of metal and will heat up quickly and could easily burn dogs' paws. It is now a requirement to ensure metal floors in utes are covered on a hot day.

"Ensure dogs kept in cages have adequate ventilation, particularly when the vehicle is not moving, and ensure all dogs are given regular access to cool water."

Victoria's Prevention of Cruelty to Animals Act requires dogs travelling in the back of utes, trailers or open tray trucks to be tethered or caged in a manner that prevents them from falling from the vehicle. The only exemption is when dogs are actively working livestock.

The tether should only be long enough to permit the dog to stand, lie down and move about but not so long that it could potentially let the dog fall off the vehicle and be dragged or strangled.

Tethering dogs should always be regarded as a temporary, short term method of restraint.

For further advice please contact the RSPCA, a local veterinarian or an Agriculture Victoria veterinary or animal health officer.