Plans to reduce the number of coastguard stations around the UK from 19 to eight are expected to be confirmed by ministers later.
The government says cutting the number of control centres will modernise the service and save money.
The Department of Transport has agreed to cut spending by 15% over the next four years.
It is understood an announcement on replacing the UK's ageing search and rescue helicopters has been delayed.
The multi-billion pound cost of replacing the helicopters is set to be passed to a foreign consortium.
At present, the UK's 19 coastguard control centres co-ordinate and manage maritime rescue efforts throughout UK waters.
Chief Secretary to the Treasury, Danny Alexander, told BBC One's Andrew Marr Show on Sunday that Transport Secretary Philip Hammond would set out details about the future of the service.
The previous Labour government proposed that private companies should take over the running of search and rescue helicopters from the RAF and that the Sea King fleet, in which Prince William has been learning to fly, should be scrapped.
Those plans were shelved by the coalition but they have been revived following a joint submission by transport and defence ministers.
The prince is based at the RAF's search and rescue headquarters at Valley on Anglesey.
The service is currently provided by the RAF and Royal Navy, plus civilian helicopters through the Maritime and Coastguard Agency.
The contract is worth £6bn over 25 years and will see the number of military aircrew reduced from 240 to 66, with civilian aircrew making up the shortfall.