Minister for Health Stephen Donnelly has said that the situation with Covid-19 is "finely balanced".
He said that the number of cases are rising and in all age groups under 75 years are rising fast.
The minister said there was a particular increase seen in those aged 19-24 years.
He said he has asked Professor Philip Nolan’s Epidemiological Modelling Advisory Group to do fresh modelling projections, and this should be read early next week.
Mr Donnelly said the recent data shows Ireland is about half way between the optimistic and pessimistic case projections.
The current view was that there may be a peak in mid-to late November.
The minister also said that the National Immunisation Advisory Committee was looking carefully at the issue of giving booster vaccines to people with underlying conditions.
He said that if approved, the Health Service Executive will be ready to roll it out.
Discussions are also under way on antigen tests being used in schools, he said.
Minister Donnelly said that what is going against the country is the rise in cases but what is going for Ireland, is the impact of vaccinations and booster jabs.
Taoiseach Micheál Martin has said that the Covid-19 booster jab is "highly impactful" and he believes that cases are reducing in the groups who have received it.
He told a private meeting of Fianna Fáil TDs MEPs and Senators tonight that while Covid-19 remains "challenging", the booster is "key" and its roll out would be "expanded" through the winter period.
The Taoiseach said the conversion rate between cases and hospitalisation is not getting any higher, but the impact on hospitals is severe and there is stress from non-Covid presentations.
The HSE has said that around 25 to 30 repeat PCR tests are conducted each month, after issues arise with the first test.
It said that repeating a PCR test and interpretation of the result can take into account the person's clinical history, their clinical condition and the reason for the first test.
The HSE said it may also take account of whether or not they were a close contact, if they had a previous positive test result and "various parameters within the test process itself".
The HSE said that as a patient's test result can be reviewed by a GP and public health at a local level, the HSE Test and Trace programme will not necessarily be made aware of all individual patient cases where a repeat test is ordered.
At the weekend, Green Party leader and Minister for the Environment, Eamon Ryan resumed his plans to attend the COP26 after a follow-up test indicated he did not have Covid-19. An earlier test indicated he had tested positive for Covid-19.
The latest figures from the Department of Health show there were 2,975 new cases of Covid-19 reported today.
As of this morning, there were 551 people in hospital with Covid-19 in hospital, an increase of 31 since yesterday.
The latest figures show that 89 people are being treated in ICUs with the virus, up six on yesterday.