Garda representatives have warned that laws requiring face coverings to be worn on public transport will be unworkable unless transport staff are willing to be involved.
The Association of Garda Sergeants and Inspectors (AGSI) have warned that gardaí have no power to act unless brought in by transport staff.
The new regulations provide for fines of up to €2,500 and six months imprisonment for not wearing a face covering on trains, trams and buses when the case is brought to court by gardaí.
However, AGSI General Secretary Antoinette Cunningham warned that garda officers can only become involved if transport staff take action "in the first instance".