And further jobs in the industry could be at risk if contractors do not accept a revised offer put on the table.
The Offshore Contractors’ Association (OCA) said it was hopeful that engineering and maintenance workers involved in the dispute over rota changes would vote against industrial action.
Unite union members will be balloted in the next few weeks.
Yesterday OCA chief executive Bill Murray warned that the threat of industrial action could cause “significant” permanent damage to the North Sea.
He said: “We’re wary that some of the older platforms, if they are shut down for any length of time because of strike action, might not be recoverable. We might not manage to get them back so the jobs that go with them would be lost.
“A lot of them are dependent on things like water floods and gas compression, if that is shut down it can take them a long time to get back up to the required pressures and there’s no guarantee that it won’t have caused significant changes in the reservoir.
“It could lead to the early decommissioning of the platform which means that the reserves there are lost – and it could be a significant cost to the UK tax payers who have to pick up 50 per cent of the decommissioning cost. Even the threat of industrial action could cause a significant permanent damage to the North Sea. It sends a clear signal to anyone considering investing in the basin that it is a high risk investment.”
The GMB and Unite unions held talks earlier this year to discuss changes to working conditions after the OCA, which represents offshore contractors, proposed changing offshore shifts from two weeks to three. The new rotas would cut down the number of crew changes on offshore installations, also cutting costs for energy companies battling plunging oil prices.
In June a new package was offered with increased sick pay and holiday pay, double standby pay and the opportunity for contractors to boost pay by £7,000 a year by taking time off during their field breaks.
The two unions recommended that members accept the offer. GMB members voted in favour of the deal but Unite members rejected it and will now be balloted on strike action in the next few weeks.
Mr Murray said the new deal was the final offer on the table and could not be improved.
And he said the risk of industrial action was already being factored into investment assessments.
He added: “The OCA wants to work with unions and the workforce to secure the long-term future of the industry and the jobs that go with it.