Infrastructure Minister Nichola Mallon has urged people to "do the right thing" after confirming that face coverings will become mandatory on public transport here from next Friday.
The rule will be applied to bus, train and ferry services and face coverings will also be required at public transport stations.
Exemptions to the regulation include those who cannot wear face coverings for medical reasons, children under 13, outdoor ferry areas and school transport.
From July 10 passengers travelling on most bus, train and ferry services will be required to wear a face covering. Face coverings will also be required in public transport stations.
A cross-departmental group will engage with the tour coach and taxi industry to explore extending the requirement to these transport modes.
Ms Mallon said everyone needs to remain vigilant as Covid-19 "is still with us".
A face covering will apply to any material that covers a person's nose and mouth - it does not have to be a surgical face mask.
Ms Mallon added: "We are asking you to take personal responsibility and do the right thing to protect the health and wellbeing of others. The fact of the matter is you can spread the virus to other, more vulnerable people without even knowing you have it.
"By wearing a face covering you are showing your support and consideration for other passengers and staff."
Unite union official Davy Thompson said several unions had called for the measure and added that he hoped people would realise the importance of masks and face coverings.
Translink Group chief executive Chris Conway said the move would mean safer travel.
"We understand this will be a big change for everyone and passengers will need time to adapt to the new culture," Mr conway said.
"Over the coming week our staff will be helping people to understand the new guidance, and in the initial period we plan to give away a quantity of disposable masks to get people into the habit of wearing their own face covering."