The two trade unions at Dublin Bus - SIPTU and the NBRU - have confirmed they will begin an all-out strike from midnight.
Pickets will be placed at all Dublin Bus garages.
SIPTU and the NBRU said workers will not operate any bus services tomorrow.
The strike will only be called off if management agree not to implement a cost-saving plan tomorrow.
Management said the plan will save €11.7 million and is necessary to protect jobs.
Earlier, Minister for Transport Leo Varadkar said that Dublin Bus management and unions should do "everything" to reach agreement and avoid disruption to the public.
He said: "Public transport should be run in the interests of the passengers who use it and the taxpayers who pay for it, and not in the interests of management or unions".
He said there had already been substantial fare increases and that payroll savings were needed to protect existing service levels.
Minister Vardadkar said there was "no more room for delay" and that both sides "should do everything to agree the necessary savings in order to avoid disruption on Sunday".
Dublin Bus has advised that the Nitelink service will not be operating tonight.
About 3,000 passengers would normally use the Nitelink service on a Saturday night.
A group representing businesses across the capital has also appealed to both sides to reach an agreement to avoid strike action.
The Dublin City Business Association said a strike would have a significant effect on businesses.
DCBA Chief Executive David Brennan said the action is planned to take place in the peak of the tourism season, with more than 285,000 people expected to pass through Dublin Airport this bank holiday weekend.
It will also affect spectators going to the All-Ireland football quarter-finals in Croke Park and those attending the Oxegen music festival.
Dublin Bus said the action would cost it €200,000 on Sunday and €600,000 on each week day.
The company has urged trade unions and employees not to engage in any industrial action that will cause inconvenience to customers and financial losses.
Customers have been advised to visit the Dublin Bus website for updates prior to travelling.
A spokesman for the NBRU said it is open to talk, while the company said it has a Labour Court recommendation to achieve €11.7m in savings.