People with Covid-19 symptoms are being urged to stay at home, even if they are vaccinated, as they could still spread the virus.
The plea from Chief Medical Officer Dr Tony Holohan came as the Department of Health reported 1,015 cases of Covid-19.
The number of people with Covid-19 who are receiving treatment in hospital is up one to 178.
29 of these patients are being treated in intensive care units - an increase of two from yesterday.
"Public health doctors around the country are reporting that outbreaks are being notified to them that originated in symptomatic people attending workplaces, or eating out, or visiting friends," Dr Tony Holohan said.
"Please remember that you should stay at home if you have symptoms even if you are vaccinated, because you could still transmit Covid-19.
"Together as a country, we need to keep on top of all the positive behaviours that limit the spread of disease, and integral to this is staying at home if you have any cold or flu symptoms," he said.
He said that going to work or meeting friends while experiencing symptoms "could be the beginning link that sets off a chain of transmission that leads to an outbreak in your community."
Dr Holohan also said that the "uplifting scenes" witnessed at walk-in vaccination centres at the weekend were "extremely encouraging."
More than 30,000 people availed of the walk-in vaccination centres that operated around the country over the Bank Holiday weekend.
"Young people have had an exceptionally difficult time throughout the Covid-19 pandemic," Dr Holohan said.
"Their willingness to come out to get vaccinated in droves is another example of the resilience they have shown throughout this challenging time.
"It is this same spirit of solidarity, commitment to keeping our whole community safe by getting vaccinated, and keeping to the basic safe measures such as staying at home if you feel unwell that will ultimately be our pathway out of this pandemic."
Earlier there were 1,082 new cases of the virus reported by the Department of Health in Northern Ireland in the last 24-hour reporting period.
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Six more deaths of patients who had tested positive for Covid-19 have been reported in Northern Ireland.
There were 224 Covid positive patients in hospital this morning, of whom 37 were in intensive care.
Meanwhile the Taoiseach has said a deal to purchase 700,000 Covid-19 vaccines from Romania has been completed.
The deal had been announced by the Government early last month.
Minister for Health Stephen Donnelly said the vaccines will be delivered throughout this month and "will allow us to continue to ramp up the roll-out of the vaccination programme"
Separately, representatives of the hospitality industry are to meet Government officials tomorrow, where the Restaurants Association of Ireland will press for a further relaxation of restrictions.
The chief executive of the RAI said he believes that the 11.30pm curfew should be scrapped from September onwards.
Elsewhere the Minister for Agriculture said he fully understands the frustrations children and parents are feeling around communions and confirmations, but that public health advice is very clear on the matter.
Charlie McConalogue said that no one will get hurt by "waiting a little bit longer" and it is important that everyone continues to adhere to the public health advice over Covid-19.
Under current public health guidelines, it is advised that religious ceremonies such as baptisms, communions and confirmations should not take place.
Baptisms can go ahead from 5 August, following all protective measures but people are urged to avoid social gatherings afterwards.