Warrnambool, Moyne and Corangamite Local Area Commander Inspector Paul Marshall said a good relationship between local police and retailers meant lower value crimes were more likely to be reported.

"Shopkeepers are much more inclined to report a $5 theft," he said.

"We (police) do not differentiate between a 50 cent theft and a $5000 theft. The courts may in terms of penalty but that's their prerogative. As far as we're concerned a theft is a theft.

"And from our perspective, these sorts of crime are pretty easy to prove and get a conviction. For thieves, it's just not worth it."

It comes as a number of south-west residents have appeared in Warrnambool Magistrates Court charged with supermarket thefts.

A 72-year-old Mortlake man appeared in court after he was caught stealing a blister pack of pain relief medication at a self-serve checkout at a Coles supermarket.

He paid for several other items but purposely did not scan the medication, which was valued at less than $5. He was subsequently fined $300.

On Tuesday, a police prosecutor said a 20-year-old Camperdown man attempted to buy flavoured milk from a Woolworths supermarket but his card declined and he left the store with other items hidden in his possession, including a box of chicken tenders that he didn't pay for.

The tactic is well known to police, the prosecutor said, as it allows offenders to pretend they have insufficient funds for a single item, in order to avoid being caught stealing other things.

A local Woolworths insider told The Standard the highest theft area was the self-serve checkouts, which came into effect in Victoria about 10 years ago.

"Sometimes the supermarket, to help out with congestion, turns off the scales to get customers through quickly. This makes it easier to steal," he said.

"Selecting produce that is cheaper than what a person is purchasing is also a common practice.

"Some people have even printed their own barcodes and put stickers over other products that can be used when scales are turned off. This may allow them to put through an expensive piece of steak as a bottle of soda water or something that has a much lower price."

The insider said some thieves left items in their trolley and simply did not scan them if the attendant was otherwise occupied.

Inspector Marshall said shop theft was usually a gateway offence to more serious offending.

"We believe that people who shop steal are also the same people who steal other stuff from cars, commit burglaries and the likes," he said.

"We want to get in early and stop those gateway offences before they lead to further, more serious offending."

The inspector said more and more shops were being armed with security systems and CCTV cameras, making it easy for police to identify offenders.

"90 per cent of the time we have clear evidence of the offenders," he said.

"CCTV cameras are becoming cheaper, easier to install and monitor, and shopkeepers have the confidence to gather the evidence we need to get a prosecution."

And while south-west police have a tough stance on petty crime, Inspector Marshall said they were still there to help those in need.

"We are seeing an increase in a theft of meats so we ask that when shopkeepers see people stealing food, to report the matter so that we can connect those people with the appropriate welfare services," he said.

"Clearly if someone is stealing food, they need help and welfare processes and referrals need to take place."

Earlier this year, Woolworths and Coles announced they were trialling new technologies to clamp down on shoplifting at self-service checkouts.

A Sydney Woolworths unveiled futuristic features including a robot that alerts staff members to hazards and new surveillance cameras.

And a handful of Coles store in Melbourne have been trialling anti-theft technology, including cameras that display real-time footage of shoppers above the self-service checkouts.

The supermarket giants also reintroduced weighing in the bagging area of the serf-service check-out area.

The weigh scales, paired with the robotic command "unexpected item in the bagging area", was switched off a number of years ago but it was turned back on at supermarkets in May.

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