Cross-Channel ferry operator Hoverspeed could be making job cuts among staff working in Dover.
Hoverspeed employs 102 staff in Dover and about 60 more in Europe
The company said it was talking to staff about "fundamental changes" it wants to introduce.
The maritime union NUMAST told BBC Radio Kent it had been asked to put forward representatives to talk to management about redundancies.
Hoverspeed runs two Seacat fast ferries between Dover and Calais, employing 102 staff in Kent and about 60 in Europe.
Hoverspeed is owned by Sea Containers, which would only say it wanted to introduce "fundamental changes".
The firm said it would not comment further until the end of a 30-day consultation period, during which time it would be discussing the position with staff on both sides of the Channel.
Hoverspeed scrapped its Newhaven to Dieppe route earlier this year and also ended its service from Dover to Ostend in Belgium.
NUMAST, the National Union of Marine, Aviation and Shipping Transport Officers, has called for the company to be "honest" about its plans for the Dover to Calais service and whether it would continue.
National secretary Paul Keenan said: "The concern is that unless the company makes its intentions clear, the closure of the service will be a self-fulfilling prophecy as people will not want to book in the traditionally busy pre-Christmas period, thereby exacerbating the situation."
Councillor Nigel Collor, of Dover District Council, said: "People have said they feel devastated and they're obviously slightly annoyed it has come to this.
"They are being told as much as they think they can now, but obviously they want to know what the future is."