The SPCA is urging dog owners to never leave pets unattended in vehicles as New Zealand braces for what forecasters say could be one of the hottest summers on record.

The warning comes as a strong El Niño weather pattern is expected to bring hotter and drier conditions across the country this summer, raising concerns about the dangers of dogs being left in parked cars.

SPCA inspectorate regional manager Jason Blair said the animal welfare organisation receives hundreds of reports every summer about dogs left in hot vehicles, accounting for about 10% of all welfare complaints during the warmer months.

“We’re in for an extremely hot and dry summer, and some dog owners simply aren’t grasping the dangers,” Blair said in a statement.

“Even if a car is parked in the shade and the windows are cracked, temperatures can shoot up within minutes.”

Dogs are particularly vulnerable because they rely on panting rather than sweating to regulate their body temperature.

“Heatstroke can occur very quickly, and the mortality rate is between 50% and 64%. It’s that serious,” Blair said.

The SPCA said many owners mistakenly believe leaving windows slightly open or parking in the shade is enough to keep animals safe.

Inspectors recently attended a callout involving two adult dogs and three puppies left inside a campervan parked in direct sunlight.

SPCA nspector Gawrav said one of the adult dogs was confined to the driver’s compartment without access to water, while another was in the rear of the vehicle.

“Both dogs were panting and barking,” he said.

After contacting the owner, inspectors discovered three puppies were also inside the van, confined to a small metal crate covered with a thick blanket and without access to water.

“I’m so relieved we got them out when we did. The results could have been tragic.”

The puppies were later taken into SPCA care and eventually adopted.

The organisation is asking businesses and retailers to display educational posters in carparks and other public areas to help raise awareness of the issue.

Under the Animal Welfare Act, owners can be fined $300 if an animal is left in a vehicle showing signs of heat stress, including excessive panting, drooling, hyperventilation or attempts to find shade.

Anyone concerned about a dog left in a hot vehicle is urged to contact SPCA on 0800 SPCA NZ or call the police.

The SPCA has also made downloadable posters and flyers available on its website to help spread the message before summer.