Investigators are calling on the public to help to catch a thief who stole $5 worth of loose change and attempted to steal a car in Hamilton in the early hours of Thursday morning.

Hamilton Sergeant Paul Stanhope said investigators believe the theft occurred in Roscoe Avenue Hamilton some time between midnight and 7am today.

"It appears that the thief gained entry via the unlocked car before stealing items and attempting to steal a motor vehicle by forcing the ignition," Sergeant Stanhope said.

"The victim returned home late yesterday, parked on the roadway outside her residence and got distracted and failed to lock the car.

"When the victim went back to the car she could not insert the key in the ignition, that's how she discovered it."

Police are appealing for anyone who might have seen a person or persons acting suspicious in the area around time of the incident to come forward.

"If anyone has CCTV or dash cam footage in the area that would be very handy," he said.

"The thief did about $600-worth of damage to the car."

On the same night, half an hour away, there was an attempted burglary at a Dunkeld business.

Sergeant Stanhope said the would-be burglar tried to break in via the back door of the Parker Street business but failed to gain entry between 5pm on Wednesday and 11am this morning.

"They tried to force the rear door, no entry was gained but multiple attempts were made," he said.

"The damage to the premises, around $300, was discovered by the owners in the morning."

The two incidences are not believed to be linked and investigations are ongoing.

Anyone with information is asked to contact Crime Stoppers on 1800 33 000 or visit crimestoppers.com.au.

Have you signed up to The Standard's daily newsletter and breaking news emails? You can register below and make sure you are up to date with everything that's happening in the south-west.