All bus services out of Limerick bus station have been cancelled after a number of drivers took unofficial industrial action in a row over new spare driver rosters.

Bus Éireann said that it has had to cancel all city and county services out of Limerick bus station after a number of drivers placed a picket at Limerick bus station today.

In a statement, Bus Éireann said it "regrets to announce that due to "unofficial industrial action taken by a small number of their employees, all services in Limerick have been impacted and are currently not operating".

The company said it is disappointed with this unofficial action and the impact it is having on its customers.

It is understood ten drivers took the action this morning, the day a new roster was due to begin for 360 spare drivers in their workforce.

The company said it had been engaged for some time in a review of spare driver working arrangements and that an agreement on the new roster was reached and binding.

The new roster was scheduled to come into operation today.

A spokesperson said the unofficial action said it has come as a complete surprise considering the review of working arrangements has been completed.

They said the review was conducted through an extensive process that was jointly agreed between the company and trade unions and was facilitated by the Workplace Relations Commission and experienced independent facilitators.

Bus Éireann said all parties agreed in advance that the determination of the Assessors and the outcome of the review would be binding on all parties.

The National Bus and Rail Workers Union said it is not party to the unofficial action.

However, an NBRU official in Limerick has disputed that there was full agreement on the new spare driver roster.

The spokesperson said the union had asked the company to pause the introduction of the new arrangements until a number of outstanding matters of concern had been resolved.

They added this had not happened and that management had gone ahead with the new roster.