People are being reminded to only use public transport for essential journeys as schools return this morning.
The National Transport Authority says there is likely to be additional pressure on bus services today.
Capacity is restricted to 25% due to Covid-19, with essential workers saying they have been left behind at bus stops due to a lack of space.
CEO of the NTA, Anne Graham, says it tends to be busier in the mornings.
"The demand is just higher than we can meet with all our public transport services out operating at the moment.
"So we're just asking people to consider could they work from home. If they can't and they do have to travel could they use walking or cycling as part of their trip.
"If that's not possible, could they consider travelling at off peak, and leave our services available, particularly for essential workers."
