A union has raised the threat of a strike by North Sea workers in a dispute over terms and conditions.

Unite claimed that contractors are using the slump in oil prices to "railroad through" changes to pensions, shifts and sick pay.

Around 2,500 workers, including electricians, plumbers , mechanics and riggers, will be asked if they want to be balloted for industrial action.

Branding the changes "opportunistic", Unite officer Tommy Campbell said: "Following the failure to agree, we will consult our Offshore Contractors Association membership asking them to consider a range of responses, including strike action.

"The downturn in oil price has seen our members' terms and conditions under attack like never before and while the threat of severe cuts hangs over them, contractors are offering no safeguards in return.

"What we want is for the OCA to work with us to preserve jobs, skills and sustain offshore safety rather than impose these opportunistic, unsustainable and unworkable changes to livelihoods.

"Oil prices will recover but knee-jerk cuts to jobs and standards will only undermine the future prosperity and safety of the industry in the long term."