Iarnród Éireann has said that while a normal weekday service is resuming from tomorrow, some services have had to be cancelled because of staff absences due to Covid-19 cases and isolation rules for close contacts.
It said some Phoenix Park Tunnel and Heuston Commuter services will be cancelled from tomorrow until Friday.
Full details of the services which will not run this week are available on irishrail.ie.
Please remember to check the operator websites and social media updates for potential delays before embarking on your journey on #PublicTransport@Luas @IrishRail @Buseireann @dublinbusnews @GoAheadIreland pic.twitter.com/C0yku84ugw
— Transport for Ireland (@TFIupdates) January 3, 2022
Meanwhile, Covid-19 is having a "significant" impact on staffing levels among gardaí, according to the Vice President of the Garda Representative Association Brendan O'Connor.
Mr O'Connor, who is a garda in Co Donegal, told RTÉ's Morning Ireland that "units are stripped down".
Gardaí are travelling further distances to respond to call-outs and some gardaí have been asked to come into work on their rest days.
Garda O'Connor said there are significant numbers of gardaí out of work due to the pandemic "and that is having an impact on our members".
"We are back to the old scenario of fewer people expected to do more, so it's an added burden on our members," Garda O'Connor added.
He also said there has been no confirmation that gardaí who are deemed to be close contacts will be asked to come to work, but it is something that has been discussed.
Members are "very concerned" about this, he added.
Elsewhere, the Chief Executive of Ibec has said that 15-18% of staff are absent due to Covid in those businesses that are open.
Danny McCoy said this rate is also "likely to be building" upwards given the scale of the case numbers and the ten day isolation period [for those not yet boosted].
He said that critical supply chains, such as food, are impacted in particular.
Derogations will be important in certain industries where workers must attend in person, he added.
"There's a lot of people who are actually healthy, can work, but are getting caught up in the close contact rules," Mr McCoy said.
The Irish Congress of Trade Unions said any amendment to isolation restrictions for close contacts "must be guided first and foremost by public health advice".
ICTU General Secretary Patricia King said: "Congress is acutely aware of the surging numbers of Covid-19 infections and the knock-on effect of requiring tens of thousands of workers to self-isolate as close contacts.
"We have to continue to be cautious in our approach to any moderation of these rules given the acceleration of cases and the unremitting strain on our health services and healthcare workforce."
Yesterday, Green Party leader Eamon Ryan said the Government is set to consider reducing the self-isolation period from ten to five days for some people who test positive for Covid-19.
The Minister for Transport said these changes would impact those who test positive for Covid-19 if they are asymptomatic or their symptoms are resolving.
The Government may also reconsider the rules around isolation for close contacts.
Speaking on RTÉ's This Week, Mr Ryan said they will look at international examples, such as the recommendation from the American Centre for Disease Control, when party leaders meet tomorrow.
Any proposals on the issue will be put to Cabinet when it meets on Wednesday.
