Deputy Chief Medical Officer Dr Ronan Glynn says the proportion of new Covid-19 cases that are due to the Delta variant has increased rapidly over the last four weeks - and is now accounting for about 70% of cases or more.
Over the past fortnight, Ireland’s 14 Day incidence has increased by 30%.
Dr Glynn says some parts of the country have been more affected than others, including Donegal, Waterford, and Dublin, but we are also seeing high or increasing incidents in Sligo, Limerick, Roscommon and Meath.
Dr Glynn said while hospitalisations remain low, there has been a “concerning” increase in hospitalisations which is being monitored closely.
Dr Glynn said there is also another concern about the Delta variant as it appears to also infect people who've received only one dose of their two dose vaccine schedule.
Donegal continues to have the highest 14-day rate of Covid, followed by Sligo.
The latest figures - up to last Friday - show the national average 14-day rate is 132 per 100,000 people, but that rises to 209 in Sligo.
Roscommon is now 6th highest in the country, with a 14-day rate of 182 per 100,000.
Mayo's rate is below the national average, at 95 per 100,000 people.