Seafarers at the Royal Fleet Auxiliary (RFA) could take strike action later this year, the RMT has warned.
On Wednesday a nine-week ballot will open after RMT members rejected a below inflation pay offer from RFA management.
RFA have offered a one year deal of 4.5 percent which is unacceptable to RMT members.
Over 500 RFA seafarers will now be balloted for strike action with the vote opening Wednesday 11 October.
RMT general secretary Mick Lynch said: "Our members are extremely angry about the pitiful pay rise they were offered and frustrated at management's refusal to even contemplate a revised offer.
"RFA seafarers do an incredibly important job and they deserve to be rewarded with decent pay rises that reflect the cost of living crisis that all workers are facing."
Notes: The Royal Fleet Auxiliary (RFA) is
uniformed civilian branch of the Naval Service, staffed by UK merchant sailors operating worldwide.
The nine week postal ballot reflects the fact that our members are working all across the world.