Beekeepers are concerned the varroa mite is showing increasing resistance to chemical treatments.
Varroa is the biggest killer of bees globally. It's been in New Zealand since 2000 and mites first began showing resistance to treatments last year.
The National Beekeepers Association says it's stepping up its efforts to identify the extent and significance of the resistance.
Chief executive Daniel Paul says the NBA is working with the Ministry of Agriculture to find a way around the problem.
"We are beginning to see signs of resistance here," he says. "We need to get a handle on how much of a problem it is, how widespread it is, how significant it is. Once we have got that clear .. we can decide what we need to do about it".
There are 420,000 hives in New Zealand, kept by 3750 beekeepers.
