As Covid-19 restrictions ease and businesses gradually reopen, the demand for public transport will increase.
But capacity has been greatly reduced because of social distancing measures, massively reducing fare revenue.
The average capacity of a Luas tram is now 15% while trains are down to 12%-16%.
A four-carriage Iarnród Éireann train can generally carry 600 passengers but the number of seats available for use is reduced to 75 because of coronavirus.
Usually there is room for 67 seated passengers on a Dublin Bus double decker, along with standing space, but now only 17 people can travel.
While Luas is operating a normal schedule, trains and buses are operating at a reduced frequency.
The National Bus and Rail Union is calling for the full restoration of all schedules on public transport.
General Secretary Dermot O'Leary said: "This is to provide for adherence to the social distancing measures recommended by the HSE and the WHO".
Commercial transport operators say reduced capacity also has severe financial implications for them.
Brendan Crowley, Managing Director of Wexford Bus, said that passenger volumes have fallen to 5% of a typical weekly volume and that capacity has been greatly reduced.
A 55-seater bus can only carry 14 people now with social distancing measures in place.
Wexford Bus has introduced other measures, including protective screens for drivers.
Mr Crowley said companies across the industry will suffer financially.
The National Transport Authority said it is working with the Department of Transport, Tourism and Sport and operators on a public transport plan in response to the Government's road map for the easing of restrictions.
It said the plan will be published shortly.