Workers in the pathology department at Royal Bolton Hospital in Greater Manchester are balloting for industrial action.
The members of the Unite union are being asked if they are prepared to strike or take action short of strikes in a dispute which could see them lose up to £10,000 a year in wages.
Workers are angry that management has walked away from talks and is refusing to negotiate on matters, including contract changes.
Bosses insist they will change existing contracts and re-engage workers on new terms and conditions.
Unite activists report that a number of similar disputes are emerging in the NHS across Britain.
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