Bus Éireann says it hopes to operate as many services as possible tomorrow - despite the fact that workers from the National Bus and Rail Union will go on strike from midnight tonight.
Around 1,100 members of the union are staging the action, in protest against €5m worth of cuts to overtime and premium payments.
Up to 10,000 passengers will be affected by tomorrow's strike - and Bus Éireann says it will cost the firm €200,000 per day action.
Spokesperson for the company, Andrew McLindon, says they are still unsure about what level of service they will be able to provide for their customers tomorrow.
"At the moment our plan is to operate as many services as we can. We do have an issue that SIPTU haven't informed us if their members will cross the picket.
"We know half the drivers, from the NBRU, will not be turning up for work but we don't know the situation with the other half of the drivers so it makes it difficult for our customers to let them know what services we can provide."
Meanwhile, with just hours to go until strike action gets underway, a spokesperson for the Transport Minister Leo Varadkar says even at this late stage, the dispute can be resolved.
In a statement he says the "priority here should be to save Bus Éireann and that a strike will only undermine the company and cause major disruption for passengers".
He added that "even at this late stage, the unions can still resolve the situation by bringing their own proposals forward on how savings should be made at the company".