The country's seven-day positivity rate continues to rise with almost one in four swabs tested yesterday detecting Covid-19.
9,192 swabs tested yesterday found the presence of the virus yesterday - the highest in a day since the pandemic began.
Test centres are currently extremely busy with little availability in urban areas.
Professor of immunology at DCU, Christine Loscher, says the rate will continue to rise for the next couple of days:
"I'm not surprised to see the figures rising that quickly, and I think it just points to everything we know about Omicron, which is how transmissible it is.
"So despite, the change in behaviour and all the other restrictions we have in place and the guidelines we can see it's starting to have an impact.
"I'd expect the number of positive swabs to keep increasing at that pace over the next couple of days."
The seven-day average of positive swabs has increased to 18%, which is it's highest level since mid-January.
There had been targeted testing everytime the rate had reached that level.
Professor Loscher fears that it may have to happen again:
"I think targeted testing is what we're going to have to do and I think the targeted testing should be people who are symptomatic because those who are asymptomatic and close contacts can quite easily use antigen testing at home.
"I think targeted testing is the only way we're going to be able to keep an eye on our case numbers."