"Due to Covid-19, the council extended the dog registration expiry period...to assist dog owners by giving them an extended period to pay dog registration fees this year," said the council's Head of Regulatory Compliance, Tracey Weston.
"As a result of this there has been an increase of 2,500 more dogs still to register, we currently have 5,328 dogs still not registered."
The council was now visiting properties believed to have unregistered dogs, but the council could not say how many property visits had been conducted.
"Registration is now due on all unregistered dogs so if you have not registered your dog yet, you need to do it," said Weston.