Three hundred and fifty Cork County Council maintenance workers have begun industrial action at over a dozen depots across the county.
The four-hour work stoppage began at 8.30am.
It follows a rejection by SIPTU of a proposal four days ago from management to resolve the on-going dispute over staffing levels in the Roads & Drivers Sections of the local authority.
SIPTU Organizer Con Casey says management's failure to replace workers as they retire has led to key sections in road maintenance, housing and other essential services being seriously understaffed.
The action will see workers refuse to co-operate with transporting private contractors, insist recognised manning levels are strictly applied and that the demarcation of roles is recognised.
Cork County Council has said that every effort is being made to minimise the impact on services during the on-going work-to-rule and efforts will continue to reach a resolution using agreed procedures.
The local authority said discussions on staffing levels have been ongoing with SIPTU for a considerable time.
Last week, they say they made a "substantial offer of additional workforce numbers" but this was rejected by the union.
