MORE than 50 offshore workers are being balloted for industrial action in what could see the North Sea strike wave spread further.

The IES Callenberg and SGS UK limited workers, who include chemists, heating and ventilation engineers, are being balloted by Unite over rota disputes.

It comes just days after the union announced strike action at Odjfell, which could shut down Norwegian oil giant Equinor’s mariner platform over the coming months.