The Taoiseach has defended the Government's plan to reduce coronavirus cases after it introduced new restrictions on travel and extended the lockdown.
Michéal Martin said he will do "whatever it takes" to keep numbers down, telling the Dáil there will be "no half measures" to ensure a "prolonged suppression" of Covid-19.
The Government on Tuesday announced that Ireland's third lockdown is to be extended until March 5, and also introduced tighter travel restrictions.
The new measures include mandatory quarantine at a designated facility for people who arrive in Ireland without a negative PCR test taken in the past 72 hours.
Travellers arriving without a negative test could also face a fine of 2,500 euro or a six-month prison sentence.
Visa-free short-term travel from South Africa and South America is suspended until at least March 5.
All passengers entering the country will be subject to mandatory quarantine, a change from the policy of voluntary self-isolation.
Mr Martin said: "I want to make a very clear that there will be no half measures from me as Taoiseach, or from Government, in ensuring a prolonged suppression of this virus.
"We will do whatever it takes to keep the numbers down once we get the numbers down, and we are achieving that."
He told the Dáil that Ireland cannot allow daily cases to return to the levels of recent weeks.
"It will be a prolonged suppression of the virus. But the key measure is human behaviour, human behaviour is what stops the spread of the virus."
Sinn Fein president Mary Lou McDonald accused the Government of introducing half measures, and criticised the Government's quarantine plans, saying all arrivals on the island should be forced to isolate for 14 days.
"What we got is a Government that is clearly at sixes and sevens, with no idea of how to proceed beyond March 5," The Dublin Central TD said.
"A Government that yet again has failed to prepare, failed to consult and failed to plan. So instead of a real plan, you have presented half measures that simply don't go far enough.
"At your press conference, contradiction and confusion between ministers was rife and clarity and certainty was in very scarce supply.
"The biggest mess from your announcement yesterday is undoubtedly your proposal on international travel, because what you announced not only goes against public health advice, it goes against common sense.
"It's not a system of mandatory quarantine. It is in fact one of voluntary self-isolation and you propose to send people back to homes and other accommodation with other people - people who may be going out to work, people who will go into our shops and stores and therefore risk the spreading of this virus.
"That to me is absolutely crazy."
Health Minister Stephen Donnelly earlier said that September remains the "aspiration" to have every person in the country vaccinated, despite issues around supply.
He said the vaccination programme is "going well", but delays to the supply of the AstraZeneca vaccine could hamper the Government's timeframe.
"September is absolutely still the aspiration. Yeah, absolutely. It has to be," he said.
"We can't promise... because it's a projection based partly on vaccinations that haven't even been applied for authorisation, and on delivery schedules that still have to be fully agreed," he told RTÉ's Today With Claire Byrne.
"I think people in Ireland are asking a very reasonable question, we're all being asked to stick with Level 5, it's been a tough, tough year.
"I think people are reasonably saying, 'based on the information you have, based on your conversations with the pharmaceutical companies, based on what the scientists are telling you, are we likely to all be vaccinated in May?' No.
"Is it likely that it will be this September? Yes."
However he appeared to row back on this, saying he cannot say it is "likely" everyone will be vaccinated by September.
"If the vaccines come through that we have advanced purchased and if they come in on schedule, then it is reasonable to think that by September every adult could be vaccinated, but with all of those very serious caveats," he added.
Vaccinations for the over-70s are due to get under way in the next two weeks, he said.