THE availability of food, water and shelter will increase rodent populations in supermarkets and other buildings.
The Ministry of Health advice to supermarkets to properly maintain their buildings in an effort to attack the rodent population follows findings from a workshop that some pesticide controls were not effective.
"The most permanent form of control is to limit food, water, shelter, and access to buildings — direct population control is necessary," ministry spokesperson Peni Namotu said. "Chemical control is generally short-term and rats will return if food and shelter are still available."
Mr Namotu said it was advisable to use proper chemicals to control rodents but under professional supervision.
"Control environmental study will reflect on efficiency and effectiveness of the product under study.
"A successful rat control strategy typically includes three elements - sanitation measures, building construction and rodent proofing, and, if necessary, population control."
He said sanitation measures should be continuous.
"Seal cracks and openings in building foundations and any openings for water pipes, electric wires, sewer pipes, drain spouts, and vents.
"No hole larger than 1/4 inch should be left unsealed, in order to exclude both rats and house mice."
The ministry is working with city and town councils to inspect supermarkets.