There is now a "very very narrow window" to bring Covid-19 under control and people must take swift, decisive and very difficult actions, Minister Simon Harris has warned.
It comes as Dubliners have been asked not to leave the county and to only have six people from one other household visit under level three restrictions that came into force over the weekend.
Pubs and restaurants across the capital are now banned from serving indoors, while Dublin weddings will cut to 25 guests from Monday.
Mr Harris said the entire country is on a knife-edge and people outside of Dublin should also restrict the number of people they meet in the coming days.
Mr Harris told RTÉ'sthat Ireland is testing more people than most other European countries.
However, he said testing alone will not bring down the numbers and people need to reduce their social contacts, maintain social distancing and stick to the hand washing guidelines.
"The reality is our testing capacity is 100,000 a week.
"We need to continue to invest in our testing and our tracing infrastructure, absolutely.
"But there's no need to mislead people and suggest that if you just increase the testing capacity, you can avoid restrictions. that is complete and utter baloney. What you have to do is both," Mr Harris said.
Solidarity-PBP TD Paul Murphy said it is "infuriating" that after six months the necessary test and tracing capacity is still not in place.
"The Government made a big deal this week about hitting a million tests. But Denmark, which has just a million more people than Ireland, hit three million tests in the last week.
"So it's completely inadequate; it's clear the Government tried to do it on the cheap, and now we're going to pay the price for that."
He said Ireland is also vulnerable when it comes to the number of ICU beds.
Social Democrats TD Holly Cairns said opposition parties want to fully support the Government on Covid but said mixed messaging is causing "unease".
"It was difficult for the general public and for us to understand why, when there were clusters in meat plants entire counties were shut down and not the plants where the clusters originated from, that's very difficult for us to understand.
.@HollyCairnsTD says some opposition parties want to get behind public health messages. She questions why entire counties shut down while meat plants with clusters stayed open. #rtetwip #rtepolitics pic.twitter.com/bTFB2J2J9B— The Week in Politics (@rtetwip) September 20, 2020
"There's other things that we lack clarity on, for example, the disparity and restrictions across maternity wards and Ireland. It's a geographical lottery as to whether you have to go through the majority of your labour alone.
"People are confused as to why they can attend a wedding with 49 people and they can't attend a prenatal of the child," she said.