Freightliner port staff and drivers at Southampton and Felixstowe docks have voted overwhelmingly to strike in a dispute about pay and conditions after the RMT union accused the company of intimidating its members.
The union has given the company until Wednesday 16 March to work towards a settlement or face the prospect of strike action that could bring operations to a standstill.
RMT general secretary, Bob Crow, said: "Freightliner chiefs made £30m between them from selling off the company, but when it comes to our members' pay and conditions we are told to be grateful for what we are given.
"The company should stop trying to divide, intimidate and victimise our members and get round the table to negotiate a settlement that reflects the contribution the workforce have made to Frieghtliner's success."
In a separate dispute, also over pay and conditions, about 100 Freightliner road motor drivers at inland terminals around the UK are voting on strike action in a ballot due to end 17 March.