PCR test centres are also open as a reduced number of clinics have been operating since Christmas Day.
However, demand for Covid-19 PCR tests is extremely high as there is currently no availability in any of the HSE centres for today or tomorrow.
As of 9.40am this morning, the entire country has no availability for public PCR testing in the next two days.
The HSE asks those looking to book a PCR test to continue to check
the booking portal as appointments might be made available throughout the day.
Vaccination clinics are currently administering Covid-19 jabs for anyone looking to receive dose one or two of the vaccine.
Booster vaccines are currently available for anyone over the age of 40, pregnant women over 30, healthcare workers over 30, and anyone over 30 with an underlying health condition.
However, from this Wednesday, everyone aged between 30 and 39 can book booster appointments.
Those who received the single dose Janssen vaccine, regardless of age, will also be able to book an appointment for a booster vaccine from tomorrow.
Almost two million booster doses have been administered in the State to date, accounting for 47pc of the eligible population.
Covid-19 cases remain extremely high as 10,404 new cases were reported yesterday, slightly down on the previous two days.
The Department of Health said it estimated that 83pc of cases are now the Omicron variant.
Studies suggest that although the Omicron variant is five and a half times more transmissible than Delta, it is leading to less hospitalisations.
As of 8am yesterday, there were 426 people in hospital with Covid-19, of which 91 were in intensive care.
Chief medical officer Dr Tony Holohan yesterday appealed to the public not to meet other households indoors.
"We know that this variant is more transmissible than even the highly transmissible Delta variant. As such, please do not socialise or meet indoors with people from other households,” he said.