Transport Minister Shane Ross has warned Cabinet ministers that bus and train services may not be able to cope with the increase in passengers returning to work in the second phase of the Government's plan to reopen the country.
In a stark warning, he told colleagues the two-metre social distancing rule means public transport operators will only be able to carry 20pc of passengers compared with normal levels of capacity.
Mr Ross said restricting this to one metre would still only allow for 40pc of normal passenger travel on some routes.
The minister was also forced to seek a massive €460m bailout for rail and bus operators who have seen their incomes slashed during the pandemic.
The warning about public transport comes as thousands of people are expected to return to work in the coming weeks after the Government cleared the way for major retailers to reopen.
However, it will insist that non-essential retail outlets do not open until 10.30am, to ease the pressure on public transport at peak times.
The lifting of the travel ban by county will also result in more people using public transport.
Bus and rail services will be forced to adhere to strict social-distancing rules to ensure the coronavirus does not spread among passengers and staff.
At the onset of the Covid-19 emergency in March, there was a 90pc drop in passengers across all forms of public transport.
Passenger numbers remained low until mid-May, and there has been a slight increase in people using buses and trains since the start of phase one of reopening the country.
The minister's spokesperson said yesterday that public transport's designation as an essential service meant that although fare revenues collapsed, most of the cost of operations remained and must continue to be met.
She said around €300m was earmarked in the budget for the cost of the Department of Transport's Public Service Obligation (PSO) and Local Link services, which funds both bus and rail operators.
Business Minister Heather Humphreys said limited international air travel will return in the coming weeks as Ireland looks to negotiate air bridges with countries that have suppressed Covid-19.
She said this is a "challenging time for everyone involved", particularly those in the aviation industry, as the "virus has no mercy", but international travel will begin to re-emerge soon.
Speaking on Morning Ireland, the Fine Gael TD said Irish air travel has been slower to be rebooted because Ireland is behind other countries in terms of our suppression of the coronavirus.
"That's why there's differences between us and other EU countries," she said.
"That said, the Taoiseach confirmed that as the world returns to a new normal, we're planning to reintroduce international air travel through air bridges.
"This would mean arranging deals with countries that have flattened the curve to a similar level as we have.
"So we will be looking at lifting travel restrictions if people are flying to and from countries where the virus has been successfully suppressed.
"But this is weeks away, and it's far too early for anyone to book holidays yet.
"However, I want to be clear we have plans in place, and we will activate them as soon as it is safe to do so."