Nautilus is seeking urgent talks with Condor Ferries over unilateral moves at the company to impose unpaid leave, cut salaries and reduced rostering commitments.
The union for maritime professionals has received complaints by members working on vessels operated by Condor Ferries over moves to introduce the punitive measures without proper consultation with employees.
The ferry operator has refused to make payment to seafarers for days owed and asked for volunteers for redundancies.
Nautilus has written to Condor Ferries asking it to take part in constructive discussions with the Union.
'We remain, open and willing to engage with representatives at Condor Ferries, in discussing the present crisis and in discussing how we can minimise the impact that this has both on ferry operations and on the seafarers whose hard work, dedication and tireless efforts, the company relies upon,' Nautilus head of industrial Micky Smyth said
In support of members, in retaining jobs and skills within the company and in securing the essential lifeline links to the Channel Islands, Nautilus has also written to the chief minister of Jersey and president of the policy and resource committee of Guernsey explaining the situation.
'Action must be taken to support the ability of the company to furlough or retain as necessary, on rates of pay that are survivable for those that are impacted. A choice between unpaid leave or voluntary redundancy, is no real choice at all.
'On behalf of the hard-working maritime professionals, who are dedicated to supplying the vital lifeblood of the Channel Islands, we ask you re-evaluate the position with respect to the availability of government support and take immediate steps in securing the salary of impacted seafarers.'
Members impacted by the developing situation at Condor should contact their industrial organiser for support and assistance.
Condor Ferries was recently acquired by Columbia Threadneedle European Sustainable Infrastructure Fund in partnership with Brittany Ferries. It is relied upon by the Channel Islands for freight and passenger transport.