Union members will also begin a 48-hour strike at 07h00 on Tuesday, November 18th.
However, Unite says it does not take strike action lightly, and is still prepared to negotiate over the best way of protecting its members' jobs.
From January, many of the port's operations will be opened to commercial contractors, a move that will affect almost 200 jobs.
Unite is angry that the Port of Dover's chief executive has stated they are not prepared to negotiate on their plans to outsource work, but only to inform the union of their proposals.
From January, commercial contractors will run many of the port operations such as mooring and tug boat work, and security services, affecting 190 jobs.
Jane Jeffery, Unite's regional industrial organiser, said: "Our members have voted overwhelmingly in a ballot for industrial action to protect their employment with the Port of Dover. Our members are determined to protect their terms and conditions of employment, and, most importantly, pensions, which will undoubtedly be threatened by these outsourcing plans."
She said that union members are angry that the company has done nothing to help resolve the situation, and feel they have no choice but to take strike action to defend their livelihoods.
"Dover Port management have forgotten the huge contribution our members make to run the port efficiently. To outsource port security at a time when security is of vital importance is negligent in the extreme," commented Brendan Gold, Unite's national secretary for Docks & Waterways. "Dover is a trust port which has a responsibility to its workforce and the local community. Clearly the port management have ignored this important fact in their relentless drive for profit."
According to a BBC news report, the Port has put in place a contingency plan with particular emphasis on safety and security, and on maintaining regular ferry services to ensure the port remains open in the event of any industrial action prior to the implementation of the new arrangements.