Portland coastguard station is one of 10 in the UK to be closed under plans announced by the government.
Ministers said the plans aimed to "improve present levels of service to the public while reducing costs".
A coastguard at Portland, who declined to be named, said he was "in shock" and "shaking with anger".
Conservative Dorset South MP Richard Drax said he would do all he could to try to save as many of the 28 jobs at the station as possible.
The plans will also see only three centres operate around the clock in Aberdeen, Dover and in the Southampton/Portsmouth area.
Mr Drax added: "I'm very disappointed. We'll aim to try to get everyone out without any redundancies, though that may not be possible.
"I've met a lot of the staff and all I would say is big is not always beautiful.
"I can see there is logic but where I stumble is that this branch in Portland is an integral part of the town and the staff do many jobs - many people go to them for help or advice - they're part of the glue of the town.
"And they know the area well. So we will lose that intimacy in exchange for efficiency and modernisation."
Shipping Minister Mike Penning said the organisation of the coastguard dated back 40 years and "cannot stand still".
Five sub-centres open only during daylight hours will be in Swansea, Falmouth, Humber, either Belfast or Liverpool, and either Stornoway or Shetland.
A small centre on the Thames in London will remain unaffected by the changes.
Mr Penning said the Southampton/Portsmouth centre would be "capable of managing maritime incidents wherever and whenever they occur and with improved information systems".
A 14-week consultation on the proposals has been launched.