It comes as the supermarket’s reopening has been pushed back by another day after a rat was spotted — bringing the store’s closure to two whole weeks.
New Zealand Food Safety deputy director-general Vincent Arbuckle said a total of 22 rats had been captured at the store since it closed on February 10 — the latest rodent being caught on Monday.
Once the store reopened, Mr Arbuckle said there would need to be "increased vigilance" at the supermarket to ensure pest control measures continued to be effective.
This would include ongoing monitoring by food compliance officers and daily updates on rat numbers.
Rats could enter supermarkets from time to time, but stores did not need to close each time as long as they were dealt with promptly and in a manner that minimised food safety risk, he said.
"With respect to Countdown Dunedin South, the problem has been serious enough to warrant a closure, so we will be monitoring to ensure its pest control measures continue to be effective.
"We don’t have a specific number of rats that will trigger further action. Rather, we will make our assessment based on a number of factors taken together, including number of rats captured, sightings on CCTV footage, and evidence of rat activity, such as waste," Mr Arbuckle said.
A Woolworths New Zealand spokeswoman said one rat had been seen early yesterday morning and the reopening of the store had been pushed back a day, to Saturday.
This marks 14 days that the supermarket has been required to shut its doors, so the company could conduct intensive pest-control work.
The spokeswoman reiterated that the closure would not pose any risk to jobs and there was "lots of work available".
