Smashing the window of a stranger's car to rescue a dog inside on a hot summer's day may seem like the right thing to do, but could it put you on the wrong side of the law?

Technically, yes.

RSPCA has recently called on pet owners to take the pledge to not leave their dogs locked up inside cars as temperatures begin to pick up.

They say leaving a dog in a car with the windows down will not prevent it from reaching extreme temperatures, and can kill them in as little as six minutes.

RSPCA Queensland chief inspector Daniel Young said anyone who came across the same situation at any time of the year should contact the relevant authorities, and said breaking in yourself was not recommended.

"I would certainly discourage people from doing that [breaking the window]. Damaging a vehicle is obviously going to be an offence there," he said.

"The issue is if you can't deem that animal as in distress and you've done that out of your goodwill to save that animal, you're going to get yourself in a lot of hot water I would have thought.

"I would say that people need to contact the relevant authorities and leave it for them to deal with."

'We've been looking at potential amendments to the act'

And as for those leaving their dogs locked up?

First aid for heat stroke Remove dog from heat immediately, preferably into an air-conditioned building or, at the very least, into the shade

Remove dog from heat immediately, preferably into an air-conditioned building or, at the very least, into the shade Wetting down the area around your dog can also help to lower the ambient temperature

Wetting down the area around your dog can also help to lower the ambient temperature Lower its temperature by wetting with cool but not chilled water and setting up a circulating fan

Lower its temperature by wetting with cool but not chilled water and setting up a circulating fan Check rectal temperature every five minutes using a digital thermometer and continue cooling process until temperature drops to around 39 degrees

Check rectal temperature every five minutes using a digital thermometer and continue cooling process until temperature drops to around 39 degrees Caution: Cooling too quickly can cause complications Source: RSPCA

There is no specific offence under Queensland law for leaving a dog in a car, or on the back of a ute.

But depending on the outcome, it could be an offence under the Animal Care and Protection Act 2001.

Not only that, but leaving the windows down on an unattended vehicle is illegal.

For a vehicle to be considered unattended the driver must be more than three metres away from it. Legally, windows must be wound up, however a gap of five centimetres or less is acceptable.

Mr Young said while leaving a pet alone locked up was not an offence, RSPCA was hoping to change that.

"It's something we've been looking at recently about potential amendments to the act to change that," Mr Young said.

"But the reality is if you leave an animal in the car, particularly this time of year, it will inevitably become an offence because you're leaving it in living conditions that aren't appropriate.

"Even though we don't see a lot of animals dying in hot cars they are still suffering and some of these animals can suffer long-lasting effects."

Never break the window yourself: RACQ

So far this year more than 670 pets have been rescued from cars in Queensland by the RACQ.

In 2015, a total of 710 animals were rescued, down from 784 in 2014.

An RACQ spokeswoman said they were equipped to get into "almost any car within minutes" and urged people not to break windows to get in themselves.

"It's a similar process for babies or children locked in cars, we don't suggest you smash the window, people can injure themselves when they do that," he said.

"Then if glass is smashed it can injure the child or animal. We can get into almost every car within minutes and safely."

The spokeswoman said if anyone came across an animal in a car in distress to call triple-0, RACQ roadside assistance on 13 1111, and to do their best to cool the car.

"If you can [get] an umbrella up, hose it down whilst you wait for people to turn up," she said.