Unite the union has confirmed that 60 of its members, employed by IES Callenberg and SGS UK, are set to resume strike action.
Starting next week, chemists, heating and ventilation engineers employed by the two firms will down tools on platforms operated by BP, TAQA, CNR, Repsol, Serica and CNOOC.
This is part of an escalating dispute over working rotas and pay.
Vic Fraser Unite industrial officer, said: “Workers at IES Callenberg and SGS have been forced to resume strike action because the companies are not listening to the concerns of our members.”
Unite’s IES Callenberg membership will take three days of strike action starting on Monday until the end of Wednesday, while chemists employed by SGS UK will start week-long action on the same day but conclude their action on Sunday.
The SGS UK dispute exclusively centres on chemists servicing BP’s platforms the Clair, Clair Ridge, ETAP and Glen Lyon.
An SGS UK spokesman said: “SGS is aware of the planned strike action, and we continue to work towards finding a resolution that will end the dispute.
“Safety and wellbeing of our personnel is of utmost importance to SGS.”
The dispute with IES Callenberg members involves around 50 offshore workers who provide heating, ventilation, and air conditioning services on offshore platforms.
Mr Fraser added: “In the case of IES Callenberg, they have gone one stage further by, in effect, stopping our members even discussing the reasons for the strike action with operators unless they are given permission to speak.
“It is bitterly disappointing that IES Callenberg and SGS have so far refused to positively engage with Unite by discussing potential changes to the working rotas. To add insult to injury, they have also failed to make any further meaningful pay offers.”
The IES Callenberg and SGS UK Limited members work 12-hour shifts for three weeks at a time, but the workers must conduct any required training during their field breaks, Unite the Union explained.
The union argued that onshore staff do not need to carry out training on their time off.
EIS Callenberg has been asked for comment on the situation.