Woolworths has unveiled its latest security technology as the supermarket group battles a rise in shoplifting activity.

The retail giant is trialling automatic gates and high-tech surveillance at self-serve checkouts at selected stores across Australia.

WATCH THE VIDEO ABOVE: How the new Woolies security gates work.

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The new security measure works by using rooftop sensors to track customers as they leave self-serve registers.

If the sensors identify a shopper who has pretended to pay or is attempting to walk straight out, the gates will stay closed and block their exit.

Woolworths spokesperson Mark van den Bosch demonstrated how the new technology works on 7NEWS.

“Because I haven’t paid for my goods, the exit gates won’t open,” he explains, while attempting to leave a self-checkout area.

Van de Bosch said Woolworths had experienced a spike in shoplifting at its stores.

“We’ve seen an increased activity of non-paying customers unfortunately,” he told 7NEWS.

Private investigator Shane Windred agreed it was a significant problem for retailers.

“I got 11 shoplifters in an eight-hour shift — it is the craziest I’ve ever seen shoplifting in my life, and I’ve been doing the job over 30 years,” he told 7NEWS.

Analysis shows that shoplifting is costing Australian retailers an estimated $9 billion a year.

And as the cost of living bites harder, meat has become a prime target for thieves — not to eat, but to sell on the black market.

“I got a shoplifter yesterday who stole $500 worth of meat,” Windred said.

“She told myself and police she was supplying in a restaurant in Canberra.”