UPDATE: A friend of Penny's owner contacted the NewsMail today and advised she had been found walking the street near Stockland by a man who helped return her on Sunday.

However the car remains missing.

EARLIER: An opportunistic thief has stolen a loved pooch and the car it was in from Stockland Bundaberg.

The owner had just taken the elderly dachshund to the vet before she accidentally left the keys in the ignition before entering the shops.

Bundaberg Criminal Investigation Branch Detective Sergeant Andrew Self said CCTV at nearby businesses filmed the car leaving the shopping centre on Friday afternoon.

"We are looking at CCTV where the car was captured driving erratically out of the carpark and in the wrong lane,” Det Sgt Self said.

He said Bundaberg had a considerable problem with leaving cars unsecured.

"People leave vehicles unlocked, keys in the ignition at shops, service stations and even at home,” he said.

"Others see this as opportunity and look for vehicles like this and take them.”

He said police had been promoting the message for years in hoping to prevent it happening further.

The silver 2011 Hyundai i20 hatch with Queensland registration 162-SVX has not been found.

Police are appealing for witnesses or anyone with dashcam footage that might have captured the alleged offence to come forward.

And police would also like to hear from anyone that may know the current whereabouts of the car or have seen the dog that was in the vehicle at the time.

If you have information, you can phone Policelink on 131 444.

You can also report information anonymously to Crime Stoppers by phoning 1800 333 000 or at crimestoppersqld.com.au 24 hours a day.