Staff at the two coastguard stations that serve Brighton and Hove will learn their fate this week.
The Conservative and Liberal Democrat coalition government is expected to announce that more than half of Britain’s coastguard stations are to close.
Ministers want to save money by reducing the number from 19 to 8, putting the Dover and Lee on Solent bases at risk.
Only three of the remaining Maritime and Coastguard Agency bases would provide 24-hour cover.
The changes will cost 250 jobs and are expected to be confirmed by the Department for Transport this week.
A spokesman for the Public and Commercial Services Union said: “We would have concerns about any cuts that compromised coastguard cover and our members’ ability to provide a speedy and effective service to the public.
“As an emergency service it’s absolutely essential that coastguards are properly resourced to ensure lives are not put at risk.”
Reports suggest that ministers will also scrap Britain’s Sea King search and rescue fleet, which includes Prince William among its pilots.
The role will instead be given to a private contractor.
In February the Labour government announced that it would pay a French and American consortium called Soteria £6 billion to run the search and rescue service over 25 years from 2012.
The number of military aircrew would be reduced from 240 to 66 with civilians expected to make up the shortfall.
Another emergency service, Sussex Police, is expected to learn this week how much it will received from the government for next year.
