The NSW Farmers Association has raised concerns for the agricultural industry as more deadly varroa mite infestations are discovered in the Hunter, Central Coast and Mid North Coast regions.
The latest detections take the number of infected sites to 137 across New South Wales.
The Department of Primary Industries (DPI) will destroy a number of hives on properties at Mooney Mooney, Clarence Town, Mitchell's Flat and Booral.
The properties are located within a 25-kilometre surveillance zone, or purple zone, around existing outbreak sites.
Peats Ridge avocado farmer and chairperson of the NSW Farmers Association Central Coast horticulture branch, Tim Kemp, said the ongoing outbreak was worrying.
"The concern is that there are very long-lasting impacts," he said.
"And not having any bees around is a very large concern for, not just avocado growers, but farmers all up in this area."
DPI plant protection officer Satendra Kumar said the number of mites detected in infected hives was low and had been identified quickly.
"The mites were caught early and that's a really good sign," he said.
"When we are finding mites in the purple zone at low levels, that is an indication we have caught up with our surveillance and we are at the forefront of where the mites have moved."
The majority of sites identified since June 2022 had been in the Newcastle and Hunter regions, but surveillance would be extended into Queensland and south to Sydney.
Sandra McDougall from the DPI said there would now be a bolstered surveillance effort to the south of the Central Coast.
"It's moved a little to the south so we do have a trench line there," she said.
"We have teams now in that surveillance side to the south doing lots of surveillance of hives in that area."
The DPI has also had to extend the eradication red zone west of Stanhope, and west of Bulahdelah, following the new detections on the Mid North Coast.
Calls for improved biosecurity
The varroa mite was first detected at the Port of Newcastle in June last year.
The Department of Agricultural, Fisheries and Forestry has confirmed to the ABC that when the mite arrived last year, its sniffer dogs were not detecting the scent of bees as a biosecurity measure.
A spokesperson said queen bees were removed from the detector dog target odour list in 2015. They were re-introduced to the list late last year.
Before the outbreak, Australia was the only continent free of the parasite.
Mr Kemp says it feels as though there has been a "failure of biosecurity."
"This is a prime example as to why the government needs to fund biosecurity properly," he said.
"If it's not funded properly you get incursions like this and it really smashes the agriculture industry."
Executive councillor of the NSW Apiarists' Association Steve Fuller said the ongoing outbreak has been devastating for beekeepers.
"It will keep impacting the industry, not just through bees being available, but the mental health of the beekeepers," he said.
"This is their livelihoods that you're playing with."
Mr Fuller says while the DPI and others in the industry have been working hard to eradicate the mite, it is a big effort.
"This is a live beast. It's changing all the time," he said.
"Even though we think we've got the finger on the pulse, tomorrow we could find it somewhere else and then we've got to do tracing and then chase it all up."
