Unite members and their families took part in rally on Saturday in Dover
Nearly 200 workers at one of the UK's busiest ports are planning to go ahead with a 48-hour strike in a row over the privatisation of their jobs.
Dover Harbour Board said it was confident it could run a "near full" service despite the walkout, due to start at 0700 GMT today.
But the Unite union said it did not believe people trained to cover for its members had the necessary experience.
Kent Police warned the strike could lead to freight and traffic delays.
Members of Unite voted about eight-to-two in favour of a strike over plans to transfer 190 jobs to the private sector in the New Year.
The harbour board said the port will remain open during the walk-out, due to end on Thursday morning, with managers and non-union staff trained in mooring and security standing in.
"We are confident we can maintain a good service to our customers and safety and security will not be compromised," said chief executive Bob Goldfield.
"The management of the port will do all it can to keep the port running.
"Freight movements, in particular, are critical to the UK economy and we have a duty to ensure this vital port in the country's supply chain is not disrupted by unnecessary industrial action."