Taoiseach Micheal Martin has said he is unable to guarantee Ireland will avoid the return of Covid-19 restrictions.
Mr Martin, speaking from the Cop26 climate conference in Glasgow, acknowledged the rise in cases is a concern.
A further 2,855 cases of Covid-19 were confirmed in Ireland on Monday evening.
The latest figures indicate there are 515 Covid-positive patients in hospital, with 91 in intensive care.
Asked whether it was possible to say restrictions will not be reintroduced, Mr Martin said: “It is possible, but there are no guarantees in relation to Covid-19.
He told RTÉ radio the rise in cases is “very concerning”.
He said he had spoken to Israeli Prime Minister Naftali Bennett during the Cop26 conference on his country’s encouraging use of booster jabs.
“The use of antigen testing is increasing and collectively if we continue to work to just be cautious in terms of our individual behaviours,” Mr Martin said.
Ireland has one of the highest uptakes of Covid-19 vaccines in Europe.
However, this has not prevented a surge in cases and growing concerns about pressure on the country’s hospital system.
On Monday evening, the National Immunisation Advisory Committee (Niac) recommended the booster campaign be extended to healthcare workers.
Health Minister Stephen Donnelly said he hoped the recommendation could be implemented “as soon as possible”.