A bee scientist says the appearance of a new honey bee parasite is the last thing beekeepers need, with the most serious pest, the varroa mite, becoming more difficult to control.
The gut parasite, Lotmaria Passim, has been found in beehives on Coromandel Peninsula and in the southern North Island.
The head of Plant and Food Research's bee unit, Mark Goodwin, said the discovery has serious implications for the bee industry because it and another parasite, Nosema Ceranae, also present in New Zealand, have been linked with bee colony collapses overseas.
Dr Goodwin said while scientists started to investigate the new parasite, beekeepers were finding it harder to control varroa which is now resistant to most available chemical treatments.
"Slowly for most bee keepers, their [bee] losses are increasing, as the resistance spreads more and more and at some stage when the losses get big enough they're going to have to change the way that they manage varroa.
"We have a lot lot of treatments, they're mainly organic treatments and also physical methods you can use to control varroa, but the problem is at the moment they all require a whole lot more labour.
"That makes it very difficult for bee-keepers. You can't manage as many hives as you did before, which changes the economics of the business, of course."
