Advice to wear face coverings on public transport is being ignored, according to transport workers.
Bus and rail workers say fewer than 1% of commuters on Monday were wearing face coverings, while social distancing guidelines were being ignored by Tuesday morning.
The figures were reported by the National Bus and Rail Union (NBRU), which said its members are at risk if people do not take precautions when using public transport. In recent days, the NBRU has warned that buses and trains could become "incubators for the virus" once commuters return in large numbers.
The union has campaigned for face coverings to be mandatory on public transport to "ensure maximum protection of frontline staff".
Dermot O'Leary, NBRU general secretary, said the lack of face coverings and protective screens for drivers was a cause of great concern.
Last week, the government issued advice to the public to wear face coverings in places where social distancing is difficult, including in supermarkets and on public transport.
Previously, both the European Centre for Disease Control (ECDC) and the World Health Organisation (WHO) have said the use of face coverings may reduce community transmission.
Policy also needs to be very clear on social distancing, Mr O’Leary said.
"We need to find some measures to instil confidence in people to use public transport. But we can't do that unless we have strict policy and guidelines - and indeed mandatory rules on face masks or face coverings in place."
Policing the wearing of masks could be a problem, he acknowledged.
"One of the other concerns we have in the NBRU, and transport workers generally would have, is that the Return to Work Protocol issued last week did not in any way cover transport."
Mr O'Leary said it is insulting that union representatives weren't "at the table" to discuss safety.
"When it comes to public health and the safety of people who both use the service and work in the service, that's an issue that we should be discussing with our expertise entering into the debate - and we shouldn't be waiting for people to hand down diktats to us," he told Pat Kenny on Newstalk.