Anger across the ambulance service is threatening to spill over into industrial action.
Workers in the Tees, East and North Yorkshire Ambulance Service (Tenyas) are balloting for strike action, while their colleagues in Northern Ireland are calling for a ballot.
The shake-up of pay and conditions under the Agenda for Change agreement has led to a rash of disputes.
There have been major disputes in the West Midlands over new pay grades and in north east England over payments during meal breaks.
Ray Gray, a Unison union regional officer, said that the dispute in Tenyas was over “a number of unresolved issues, including lack of meal breaks, changes to shift patterns, roving standby and staff unable to take leave”.
In Northern Ireland the Unison branch has sought permission for a ballot because of “a breakdown of industrial relations between Unison and the management of the ambulance service”. Union members have accused management of implementing an “anti-Unison agenda”.