The massive increase in hives being euthanised comes as the number of infested premises grows.

The NSW Department of Primary Industries has confirmed three new detections of the parasite in the Newcastle area, north of Sydney, taking the number of infested premises to 62.

A new emergency order has been issued to include the new sites, but the overall area covered by the eradication zones had not changed significantly.

"Tracing and surveillance efforts have confirmed the presence of varroa mite in one property at Brandy Hill and two properties at Phoenix Park," the DPI's deputy chief plant protection officer Chris Anderson says.

"The positive news is that so far all confirmed cases either have clear links to existing cases or are geographically related, so we continue to focus our efforts on eradication."

The mite was first detected around the port of Newcastle on June 22.

The DPI's Satendra Kumar said the mite may have been present in Australia for up to 12 months before that.

"It's hard to pinpoint...based on what we have heard, what evidence we have gathered it's from six to 12 months," he told AAP.

He says authorities are still confident they can contain the mite.

"It may be reasonably contained at this stage," Mr Kumar says.

Last week a varroa mite detection was confirmed at a property in Nana Glen, northwest of Coffs Harbour, impacting the pollination of berries, avocados and macadamias.

Mr Kumar says of the 30 hives inspected in that area since then, only one mite has been found.

"The infestation levels are pretty low, and the hives are immediately destroyed."

He's hopeful that eradication zones which prohibit the movement of hives will be removed as the mite is contained in that area.

NSW beekeepers can only move their hives with a permit.

Australia had been the only major honey producing country free from varroa mite, the most serious pest of honeybees worldwide.

Australian Associated Press