The number of rodent sightings in homes and businesses across the country has increased by roughly 50%.
Pest controllers believe new regulations on the use of rat poison could be a factor in the surge in cases.
The National Pest Technicians Association is due to meet with officials from the Department of Agriculture to discuss the issue tomorrow.
Technical Field Consultant with Rentokil, Richard Faulkner, says the weather is playing a role too.
"The legislation only really came into play last year. Definitely there could be factors involved with it," he said.
"We've got to look at other things first as well, environmental change is really the big thing. When you look at our winters now, our winters are very mild so seven or eight years ago we'd have got a couple of weeks hard frost. That would have increased the rat mortality rate externally."