Ram-raiding youths who have plagued Auckland businesses are now favouring jewellery store smash and grabs, with at least two occurring in the city every week.

Police are boosting patrols around the city's hotspots, but say the nature of the crime means extensive work is required to locate and address offenders' behaviour.

The recent spate has reportedly shaken confidence in the retail industry, causing more business owners to provide health and safety training courses for their staff.

Police Minister Chris Hipkins has been briefed on what officers are doing to target recidivist offenders and cited what he considers a "good success rate" in holding them to account.

However, National Party police spokesman Mark Mitchell believes repeat offenders are getting let off lightly on account of their age and the focus should be on protecting law-abiding citizens.

The NZ Herald has reported many of the brazen aggravated robberies and burglaries hitting Auckland jewellery stores, with Michael Hill Jewellers being a common target.

In an exclusive interview with the Herald, Auckland Detective Inspector Scott Beard said at least 12 smash-and-grabs had occurred across Tāmaki Makaurau in the six-week period from the end of May to mid-July.

He noted Michael Hill had been targeted in roughly half of those incidents.

Beard also revealed police believed the offenders carrying out these crimes were many of the same people behind a significant spike in ram raids earlier this year.

Offenders are often armed with crowbars, hammers or other metal bars so they can break the glass. Photo / Hayden Woodward

"It would appear that we're talking about the same group of offenders and they've just moved into the aggravated burglaries where they're walking into a, for instance, Michael Hill Jewellers, smashing the glass cabinets, grabbing the jewellery and taking off," he said.

"I think a lot of this is around notoriety, bravado amongst their friends and their group, but also there's that opportunity to sell or get money from jewellery or wear it themselves."

Offenders were typically between 12 and 20 years of age, often equipped with hammers, crowbars or other metal bars.

They regularly targeted stores around closing time, when there were likely to be fewer customers.

Stolen goods were then either sold online, sold to a second-hand dealer, distributed through friend groups or worn by the offenders themselves.

It was a problem facing all three of Auckland's police districts, Beard said.

He said it was common for police to find the getaway vehicle, sometimes recovering stolen jewellery offenders had left behind in their haste.

However, he couldn't point to the proportion of offenders being located after the fact, but he was aware of search warrants being executed last week.

Auckland Detective Inspector Scott Beard warned staff members against engaging with offenders. Photo / Alex Burton

While the offenders themselves sometimes weren't known to police, Beard said they were often linked to families that were, aiding efforts to track them down.

In response to the recent uptick, police patrols at shopping malls and other hotspots at closing time had been enhanced.

Police were also engaging retailers, including Michael Hill, on implementing preventative measures.

Given many offenders were masked, Beard said it took extensive forensic investigation to establish who had committed the crime.

However, Beard hoped through assistance from police's Youth Aid team along with district-wide co-ordination, the frequency of smash-and-grabs would reduce as it did for ram raids.

A person was caught on film stealing from a West Auckland Michael Hill Jewellers store last week. Photo / Supplied

He advised any business managers who witnessed suspicious activity to close their stores early and if they were hit, to not engage with offenders.

"It's only property, don't let your staff get involved or assaulted in any way."

Retail NZ chief executive Greg Harford said the spate had shaken confidence in the sector, particularly for jewellers.

"The jewellers that we're talking to are certainly concerned about the safety of their people and their customers.

"It's just a truly terrible thing if they're being done over in the current climate."

He noted more businesses had been reviewing their security arrangements and enrolling in health and safety courses for their staff.

Harford felt a campaign from central Government was necessary to target the notoriety such incidents afforded offenders on social media.

Police Minister Chris Hipkins. Photo / Mark Mitchell

In a statement, Hipkins said he was buoyed by the approximately 150 arrests and 750 charges that had occurred since February in relation to ram raids.

"Police are focusing significant investigative effort on the recent spike in retail offending, including ram raids, and have a good success rate in holding offenders to account for these offences."

National Party's Mark Mitchell told the Herald he felt the punishments being handed down to repeat offenders weren't sufficient.

"The priority is that law-abiding members of our society are kept safe and as much as we all don't like prisons, the fact of the matter is this, if someone keeps offending and they're violent, then the safest place for them and the community is in prison."

Attempts to contact Michael Hill for comment were unsuccessful.