President Michael D. Higgins says his own office advised he use a government jet to visit Belfast and not the PSNI.
The incumbent had said he had to fly to Northern Ireland last May as the Northern Irish Police Service couldn't provide the required security by road.
This claim was disputed by the PSNI over the weekend.
Speaking in Drogheda today the President said "I have visited Northern Ireland many times in the last seven years. I take the advice from my office and my office judges these trips in terms of logistics and security".
"I want to say how grateful I am to the PSNI for not just the assistance that they provide in relation to my security but also for the courtesy the men and women have indicated to Sabina and I, and those travelling with me and long may it continue".
Meanwhile, presidential candidate Liadh Ni Riada has sent a letter to President Higgins asking him to explain his use of public money.
The Sinn Féin MEP says the incumbent has serious questions to answer before the final debate of the campaign tomorrow night.
She says Michael D Higgins has to explain his use of the government jet to fly to places in Ireland at the taxpayer's expense.