New Zealand Food Safety deputy director-general Vincent Arbuckle said yesterday Dunedin South Woolworths, formerly Countdown Dunedin South, had been monitored for a "significant period" and the MPI was satisfied its rat issue had been resolved.
However, Mr Arbuckle could not say how the store came to be infested or when the MPI investigation would be complete.
The government agency understood people were interested in the outcome of the investigation and would share more information "when we can".
"The investigation by New Zealand Safety into the Dunedin South store continues," he said.
"As with all investigations, we do a thorough job, keeping an open mind and following the evidence, so we are unable to give a definitive timeframe for completion."
On February 14, Mr Arbuckle said broadly the purpose of the investigation was to "establish the causes of the problem and make whatever changes are necessary to prevent it from happening in future".
He said on some occasions investigations would look into whether enforcement or prosecution action was necessary.
At the time, the supermarket in Andersons Bay Rd was in the midst of an 18-day closure that grabbed national attention and seemingly sparked pest sightings in other supermarkets, including a video of a mouse in a deli in Christchurch and reports of a pigeon roosting on food shelves in Auckland.
The supermarket reopened on February 28, but not before more than 20 rats were captured in the store and rats nests were discovered in the walls.
Woolworths has apologised, and at the time said the incident was "not acceptable to us or to our customers".
