Bus drivers and engineers are set to strike across West and South Wales on Monday of next week.
They are members of the Unite union employed by the First Cymru group. Bosses have offered a below inflation pay deal for the coming 15 months. Talks were planned for Tuesday of this week.
If the strike goes ahead it will affect services in Bridgend, Maesteg, Port Talbot, Neath, Swansea, Llanelli, Carmarthen and South Pembrokeshire, as well as the Greyhound buses between Swansea and Cardiff.