Belfast City Council says it has "doubled" its vermin control efforts in the city centre in the wake of the Primark fire, as one expert warned that rotting food left in cordoned-off shops is a "paradise for rats".
Six of the 14 businesses still cordoned off are believed to have had food on their premises at the time of the August 28 fire and staff in some stores are understood to have been unable to return to dispose of perishable stock.
Among the stores or eateries in the cordon area are Tesco Metro, McDonald's and a Spar.
The council says that its pest control team was "baiting sewers" around the safety cordon at the weekend and has "targeted significant resources in this area to reduce the potential of attracting vermin".
It added that it has "enhanced city centre street-cleansing resources in the areas which are being used as alternative routes".
But the council stated that, 14 days after the blaze occurred, there is "still no access to premises within the cordon".
Owner of Entomol Ltd, Gary Stewart, who has been in the pest control business for 27 years, said there could be a "huge increase" in the rat population, and rotting food could also attract flies and maggots.
"The city centre is known for its rat problems and if the food is left to rot in these shops, it will be paradise for them - a rat magnet," he said.
"You could have a huge increase in the rat population, it could explode. It's right to bait the sewers, but if the rats are already above ground and have a food source, it's like a wee rat hotel - why would they leave?
"It's a difficult one if the pest-control team can't get into the premises and put bait stations around. Their hands are tied.
"This needs to be looked at with some urgency," she said. "There could be rats, mice and maggots within those shops and they might need a deep clean before reopening.
"It has been two weeks - it could contribute to a public health risk and I think it has the potential to make the rat problem worse. But I appreciate the safety concerns for those going in to carry out work."
A Tesco spokesman said: “We continue to work closely with the Council and other key authorities on a daily basis. Health and safety remains front of mind for everyone onsite.
"Our specialist contractors are ready to start returning the store to normal as soon as we have permission to access the site.”
A McDonald's spokesperson said: "We are currently unable to gain access to the Donegall Place restaurant due to the recent fire. We continue to engage with Belfast City Council on this matter."
A Spar spokesperson said that the owner of its Royal Avenue store was granted access to the premises by the council "for a short time" on the morning of August 29 and that "all perishable food was removed from the store at this time".
The spokesperson added: "No perishable food has been in the store since August 29. We are awaiting further instruction from Belfast City Council to access the remaining, non-perishable goods in the store."
No response had been received from Tesco at the time of going to press.
A council spokeswoman said: "Staff from Belfast City Council's environmental health team have been on the ground carrying out regular assessments around the exclusion zone. Our pest-control team was out at the weekend baiting sewers in the area around the safety cordon.
"We have doubled our efforts and targeted significant resources in this area to reduce the potential of attracting vermin, and council will continue to keep this under review.
"Council has also enhanced city centre street cleansing resources in the areas which are being used as alternative routes.
"A number of food businesses remain within the cordon.
"There is still no access to premises within the cordon, but as soon as access can be safely facilitated, council will assist traders who wish to access their property. However, this will be done on a case-by-case basis, depending on locations, risk assessments and legal waivers."