Hundreds of North Sea workers are to be balloted for strikes in a dispute over pay.
Members of Unite working for the Wood Group on eight of Shell's North Sea oil and gas platforms will vote in the coming weeks on whether to launch a campaign of action.
The union said its members faced proposed pay cuts of up to 22%, rising to 30% once cuts to other allowances are added.
John Boland, Unite's regional officer, said: "Our members are deeply worried and frustrated and feel that they have no other option now but to consider strike action.
"Nobody here wants to take industrial action but Wood Group is being unreasonable - pay cuts of up to 30% are totally unjustified and we won't stand for it.
"Our members have already given a lot of ground because we understand that with a low oil price the companies had to make changes to maintain profitability.
"For the benefit of the North Sea as a whole we must not roll over again. This is our only opportunity to stay strong and say no, not just for us but for the whole of the North Sea."
A Wood Group spokeswoman said the situation is "extremely disappointing".
"Safeguarding long-term employment opportunities for our employees on these assets is our priority and proposals regarding changes to terms and conditions are being reviewed with this as our firm focus," the spokeswoman said.
"The terms and conditions under review have been approved by the OCA and the recognised unions. During the consultation process we have attempted to reach an agreement with our employees by offering an enhancement to these terms and conditions, aligned with their competency and experience.
"We are extremely disappointed to be in this position during the consultation process. We remain fully committed to continuing to engage with our employees and the unions and are focused on reaching a positive resolution, which meets our mutual goal of sustaining these jobs in the North Sea, now and in the future."