They argued the bonus rate offered by BYLOR – made up of French firm Bouygues TP and Laing O’Rourke – is “insufficient to attract the quality of workers needed to ensure the civil works phase of the £18 billion project is completed on time”.
They had warned the construction of the new nuclear power station could be delayed if the dispute was not resolved.
GMB and Unite unions added fresh talks are currently being scheduled to come to an agreement and avert the need for industrial action.
They said discussions are being tabled following “positive intervention of the client EDF”.
Jerry Swain, Unite Acting National Officer for Construction said: “In the face of a looming industrial dispute, the client has shown good sense and has stepped in to try to resolve the problem.
“It is hoped that when fresh negotiations commence, BYLOR and in particular Laing O’Rourke are prepared to enter into practical discussions and a sensible bonus which meets the expectations of the workforce and ensures the project is delivered on time, can be agreed.”