Ambulance crews are threatening industrial action after attempts to resolve a row over a pay row failed.
Workers want to be paid if interrupted during meal breaks
North East Ambulance Service Trust (NEAS) staff were offered a rise of up to £1,800 to be on call during breaks.
But the offer was rejected and paramedics are planning to take action on 27 and 28 January when they will refuse to do overtime.
NEAS chief executive, Simon Featherstone, said he was "astonished" by the move.
Unison's North East branch secretary, Joel Byers, said the offer was rejected because members learned that ambulance workers elsewhere were offered a better deal.
That deal involved a shorter working week with meal breaks, but no pay rise.
In November, the ambulance trust introduced a £20 payment as an interim measure for crews who volunteered to answer 999 calls during their meal breaks.
But Mr Byers said staff should be paid time and a half if they were called out during breaks or be allowed to be off duty.
He said: "Why are they asking paramedics and technicians, who are highly trained, being asked be a voluntary force for two hours a day? We are a professional service, not volunteers."
But Mr Featherstone said: "I am surprised and astonished at this action. We have made significant efforts to resolve the meal break issue locally, yet all our offers have been rejected.
"This £20 payment is voluntary and was introduced in response to staff claims that they wanted to be aware of calls during their breaks.
"So we find it hard to understand why in is now being opposed. We remain available to discuss a solution to this issue."