Unions representing workers at the Isle of Man Steam Packet company are set to step up their campaign to defend ferry services.
The RMT union claims attempts are being made to undermine the Steam Packet using vessels crewed by seafarers on "poverty pay and appalling conditions".
Demonstrations will be held on the island and in Liverpool on Tuesday.
The company has said it was reviewing its operations following the launch of a rival freight service last month.
The Ramsey-based Mezeron's daily freight service between Douglas and Liverpool is a direct competitor for the Steam Packet, which operates services from Liverpool, Heysham and Birkenhead to Douglas.
Protesters want the government to come up with a contingency plan in the event of the Steam Packet Company cutting back services.
RMT general secretary Bob Crow said: "The Steam Packet is a cornerstone of the Isle of Man economy with nearly 200 years of history and we are demanding that the island's House of Keys intervenes to secure the future of this vital freight and passenger link."