The Government agreed on 30 December 2020 that Level 5 as set out in the Plan for Living with COVID-19 will apply nationally.
The Department of the Taoiseach has published the List of Essential Services at Level 5 (available at the link below).
Essential workers are those providing the services set out in the list. Physical attendance at workplaces is only permitted where such services can only be provided in person and cannot be delivered remotely.
The legislation underpinning the current restrictions is set out in the Health Act 1947 (Section 31A - Temporary Restrictions) (Covid-19) (No. 10) Regulations 2020 (S.I. No. 701 of 2020) provides that banks, post offices and credit unions are essential retail outlets (Schedule, Part 1A); and that financial, insurance and banking services (including post office and credit union services) provided by a financial services provider are essential services (Schedule, Part 2) for the purposes of those Regulations.
List of Essential Services at Level 5:
https://www.gov.ie/en/publication/c9158-essential-services/?referrer=http://www.gov.ie/en/publication/dfeb8f-list-of-essential-service-providers-under-new-public-health-guidelin/