The HSE has asked people not to go to the UCD walk-in Covid-19 vaccination centre after large queues formed on Thursday morning.
The booster vaccine clinic is offering shots to those aged 50 to 69 and all healthcare workers from 8am to 10am.
However, at 8.40am the HSE wrote on Twitter that there were “very large queing times” at the clinic and said “please do not go there as the centre is at capacity”.
Photographs circulating on social media appeared to show hundreds of people queuing from before dawn.
Damien McCallion, the HSE’s national lead for vaccinations, told RTÉ’s Morning Ireland that every walk-in centre “has a certain level of capacity”.
He said the HSE would provide daily updates on “where there are queues and show options”.
According to the HSE’s website, the are two other walk-in clinics offering booster vaccines in Dublin on Thursday, one at the National Show Centre in Swords and another at Croke Park.