The Department of Health has been notified of 2,029 new cases of Covid-19.
There are 448 patients with the virus in hospital, down 16 since yesterday, with 88 in intensive care, up two.
The five-day moving average of cases is 1,906.
In a statement, Chief Medical Officer Dr Tony Holohan said: "We have seen a significant increase in transmission over the course of the last fortnight.
"We currently have in excess of 500 cases per 100,000 of the population and disease incidence is rising in all age groups and in every part of the country."
"As we come into the bank holiday weekend, take particular care with the three Cs - crowded places with many people nearby, close contact settings, especially where people may not be vaccinated, and confined and enclosed spaces with poor ventilation," Dr Holohan added.
Earlier, Health Service Executive CEO Paul Reid said that given the trends, there would most likely be more than 2,000 new cases reported today.
Speaking at a HSE briefing, he said that positivity is rising with "quite concerning levels across the country and particularly in certain pockets of the country".
"More people are testing positive and more people are symptomatic."
He said that there has been a "very significant shift in the age and the average age of those testing positive" moving to 34 now.
More older people are getting sicker, he added.
Emergency departments have also seen an increase in the volume of patients attending.
"We've also seen an early identification of the flu virus, which will cause us concern as we head into winter, and again a call to those people to come forward for the flu vaccine who are eligible for a flu vaccine."
Mr Reid said that people are already waiting a long time for Covid-19 care. He added that with the latest pressures, they could be waiting even longer.
All indications are this will deteriorate, in terms of hospitalisations and ICU, Mr Reid says. He adds it won't be to the same extent seen in January, while a peak could be reached in November | Read more: https://t.co/YiekYpI1Uh pic.twitter.com/jc8rEw16m7— RTÉ News (@rtenews) October 21, 2021
He said that in around one week, the HSE will begin vaccinating around 800,000 people aged 60-80 with booster jabs.
There will also be use of antigen tests for close contacts with no symptoms.
He said that ICU figures show that 52% of patients were not vaccinated, 41% fully vaccinated, and 5% partially vaccinated.
Speaking about maternity services, Paul Reid said two maternity hospitals who have allowed more access to patients' partners have not seen any evidence of spread of Covid-19 infection.
He said that from 1 November, all maternity services will allow further access for nominated support partners for women to visit under normal hours.
From 1 November, all maternity services can provide access for nominated partners to access inpatient areas during visiting hours, HSE CEO Paul Reid says | Read more: https://t.co/44rQQhzR1n pic.twitter.com/CJUZFd4aMZ— RTÉ News (@rtenews) October 21, 2021
Meanwhile, HSE National Lead for Vaccination Damien McCallion said that in the last 14 days, around 1,000 people a day have come forward for first time vaccination.
Yesterday, he said, 2,500 registered, involving all age groups.
People as old as 80 still coming forward for their first vaccination, HSE's Damien McCallion says. He says there are people of all ages still coming for their first jab | Read more: https://t.co/YiekYpI1Uh pic.twitter.com/TkolfcExxo— RTÉ News (@rtenews) October 21, 2021
It comes as the number of Covid-19 outbreaks increased last week, including in the workplace and in schools, according to figures from the Health Protection Surveillance Centre.
There were 199 outbreaks or clusters in the week to last Saturday, compared with 174 the previous week.
A total of 34 workplace outbreaks, leading to 120 confirmed linked cases, were reported.
It compares with 19 workplace outbreaks the previous week.
An outbreak of Covid-19 is two or more linked cases.
There were 15 outbreaks in schools leading to 80 linked cases, compared with three outbreaks in schools the previous week.
Acute hospitals saw 13 outbreaks with 86 linked cases, up slightly on the previous week.
In nursing homes, there were 11 outbreaks, resulting in 180 linked cases, also up slightly on the previous week.
Covid surge having impact on 'multiple fronts'
The surge in Covid-19 cases is having a significant impact on multiple fronts, according to a consultant oncologist.
Professor Seamus O'Reilly, who works across three Cork hospitals, said the impact is being felt in emergency departments, with ICU capacity and staffing issues.
Speaking on RTÉ's Morning Ireland, Prof O'Reilly said emergency departments are full.
He said there are staffing problems due to breakthrough Covid-19 infections among vaccinated healthcare workers, which showed that immunity is waning.
There are issues with bed capacity in ICUs, he said, and complex surgeries may be deferred if an ICU bed is not available.
Prof O'Reilly also said he is seeing a "surprising" proportion of patients who are not vaccinated and said there needs to be a "targeted campaign" to find out the concerns of the unvaccinated and groups that are marginalised.
A GP in Co Kerry said it is difficult to speculate as to why Covid-19 cases have suddenly risen sharply in the county, after a prolonged period of low infection rates.
Dr Gary Stack, who is also the Medical Director of SouthDoc, said there has been a significant rise in all respiratory symptoms and presentations and the out-of-hours figures last week were a 23% increase on the same period last year.
He said it would have been good if the further easing of restrictions could have been postponed for another four to six weeks.
In Northern Ireland, the Department of Health has reported 1,051 additional cases of Covid-19 and four deaths in the past 24 hours.
A meeting of the Stormont Executive was told that community transmission of the virus remains "roughly constant at a high level".
The update paper from health officials said Covid-19 intensive care numbers remain steady at between 30 to 40 and death rates continue to be low.
Ministers were told that modelling suggests that transmission is set to plateau at the current high level for the next six weeks, with the possibility of modest falls or rises in case numbers and hospital pressures.
Additional reporting Fergal Bowers