Just one in four under-12s have been registered for a Covid vaccine so far.
A total of just over 11,000 under-12s have been vaccinated over the last two weeks.
So far only 12.5 per cent of 5 to 11-year-olds are double vaccinated with 22.6 per cent having been given a single dose.
The HSE estimated over 100,000 children who got Covid over Christmas may now be eligible for their vaccine.
Dr Lucy Jessop is Director of Public Health at the National Immunisation Office, she said they were expecting the take-up among children to be slower.
Dr Jessop said: "Parents have told us that they need time to think about whether they are going to bring their children forward for vaccination, so we want to give them plenty of time, and we want to give them all the information that they need to make that decision."
She added: "I think it's partly around time, also we know before Christmas there were lots of children that were infected with Covid, unfortunately.
Actually I think there might be a little confusion in some parts, you only need to wait four weeks [after infection] rather than three months. It's three months if you're having a booster but for children who haven't been vaccinated before, they only have to wait four weeks, so those children who did have Covid over Christmas can now come forward for their vaccination."
