The bee industry is running out of time to find long term solutions for controlling varroa.
The parasite is regarded as the most damaging honey bee pest in the world.
The country's leading bee scientist, Mark Goodwin of Plant and Food Research, is predicting that most chemical treatments for the varroa mite will be ineffective within five years, and says there are no readily accessible solutions on the horizon.
Dr Goodwin says there have been no new chemicals available for 20 years.
He says beekeepers north of Auckland and in Waikato are already encountering chemical resistance in varroa and that will spread.
He predicts resistance to two of the main three chemicals being used will spread throughout the country within five years.
Dr Goodwin says if people are left to rely on just one chemical, resistance to it will develop even faster.
He says scientists are investigating non-chemical varroa control options but most of those are years away.
One of the areas of research underway is breeding bees that are resistant to varroa.
Hundreds of beekeepers have been attending workshops on the results of a research project designed to develop varroa resistant bees.
National Beekeepers' Association president Barry Foster says there are challenges in that, but beekeepers have other ways they can slow the impact of chemical resistance in the meantime.
He says they have the option of alternating treatments between different chemicals.