Yes. EU regulations require checks in respect of pet movements for pets entering the EU (including NI) from third counties.
On 1 January 2021 it is expected that a number of pet owners will be unable to comply with the EU Pet Travel Regulation, for movement of pets between GB and NI, for example, pet owners who have already travelled from NI to GB and intend to return following the Christmas period. Pets travelling from GB to NI will therefore not be subject to routine compliance checks until 01 February 2021. However, officials will reserve the right to undertake checks should there be a suspicion of illegal activity or welfare concerns.
After January 1st, 2021, when returning from GB to Ireland, your pet, even if the pet was born and is resident in Ireland and has an EU pet passport. You will have to visit a veterinary practitioner in GB to have your dog treated against Echinococcus multilocularis (tapeworm) before you re-enter Ireland. These details must be recorded in the EU pet passport by the veterinary practitioner in GB.