Detectives across four of the region’s local area commands have been called in to look at hold-ups in their area since the Miners Lamp Chinese restaurant at Weston Workers Club was targeted four days after Christmas.

But it appears the number of unrelated criminals, and not just the volume of robberies, has the investigators working overtime.

Historically, armed robbery spikes can be blamed on a small number of gangs or individuals ‘‘running hot’’ at the same time.

But there could be as many as 10 groups and individuals responsible for the 28 armed robberies since December 29, which equates to almost a quarter of all of the hold-ups reported across the Hunter in the year to September last year.

Charges have been laid over a series of incidents across the Coalfields, but it appears another professional group of armed robbers are netting tens of thousands of dollars through targeted clubs and pubs.

Edgeworth Bowling Club employees became the latest to be threatened with a gun when two balaclava-clad bandits pointed a long-barrelled rifle at them as they were counting the weekend takings after closing on Sunday night.

The Newcastle Herald understands the newly formed Strike Force Finite will look at links between the Edgeworth bandits and those who targeted the Shortland Hotel on January 23 and the Broadmeadow Newsagency and Post Office on February 2.

‘‘It takes a lot to be able to do these bigger jobs properly,’’ Detective Inspector Graeme Parker said yesterday.

‘‘We are talking about criminals who appear to be well planned and organised.’’

But what is also concerning police is the number of offenders.

It includes three occasions where young children, some estimated to be as young as 10, being involved in opportunistic robberies of newsagents and service stations.

There have also been a range of opportunistic offenders, possibly drug users trying to get cash to fund their habits, who have stormed softer targets.

Of the 28 armed robberies since December 29, police have laid charges involving 11 of them.