Commuters who refuse to wear face coverings on public transport could be hit with fines in the coming weeks.
Transport chiefs are investigating ways to increase the use of face coverings on public transport, which became mandatory yesterday.
Anne Graham, chief executive of the National Transport Authority (NTA), said it is likely in the coming weeks that fines will be issued to people who refuse to use them. Detailed regulations are being prepared by government departments at present.
This week, she said, passengers will be "encouraged" to wear them but enforcement will increase in the coming weeks. Ms Graham told Newstalk this would take the form of fines.
"That's being worked on at the moment," she said.
As public transport becomes busier, it is important for people to exercise personal responsibility, she added.
Professor Paddy Mallon, a consultant in infectious diseases, said there needs to be visible enforcement of the rule or people simply will not heed it.
Dermot O'Leary, general secretary of the National Bus and Rail Union (NBRU) said people will ignore the rule if it is not enforced or policed.
Speaking on RTÉ's News at One, Mr O'Leary said passengers remain confused about whether they have to wear masks or not, and many are simply choosing not to do so.
He said bus drivers are reporting a very low uptake in the mandatory policy of wearing face masks, which the NBRU has campaigned for in recent months to protect staff and passengers.
He said the government's "dithering and indecision over the last number of weeks on this issue" has confused passengers.
Capacity limits on public transport have also increased this week, from 20% to 50%.
This should be good news for users of all transport services but, in particular, for those looking to use Bus Éireann's Expressway services.
Over the weekend, the transport company's Twitter account posted dozens of messages warning that capacity had been reached on services all over the country and advising people to look for alternative services.
While the capacity increase appears to have helped ease this issue, there were still two services on the X8 route between Cork and Dublin identified as reaching capacity at midday on Monday, leaving passengers forced to look for alternatives.
#EXPServiceUpdate ** BUS FULL **
EXPRESSWAY X8 Cork/Dublin 12:00.
Bus full leaving Cork – seat capacity is limited due to social distancing requirements.
Please check https://t.co/jaXoYgWrsN for alternative services.— Expressway #Wearafacecovering #HoldFirm (@ExpresswayIRE) June 29, 2020
A spokesperson for Bus Éireann said it is not possible for them to increase frequencies or add additional buses to busy routes.
"Expressway services are currently experiencing high demand on specific routes," they said.
"All of our available resources in terms of vehicles and drivers are currently deployed and we have introduced a new online seat reservation system providing a guaranteed seat for passengers on the X8 route.
"We will continue to update our Expressway live Twitter feed in relation to capacity on our services @ExpresswayIRE."
The NTA said capacity increases should help to alleviate "considerable pressure" experienced by public transport operators as the economy began to open up in recent weeks.