The Defence Secretary says the Royal Navy's fleet is struggling to meet demands.
Britain's fleet is made up of 76 ships, but Ben Wallace says a quarter of them cannot be put to sea.
Mr Wallace was answering questions to MPs on the Defence Select Committee.
"If I had more of our current fleet working then I would have much more freedom to deploy to meet some of our ambitions and tasks," he said.
"I've made it very clear to the First Sea Lord one of my priorities is to get what we've got working."
Just three of the six Type 45 destroyers, costing £1 billion apiece, are in service.
It emerged this week that the operational handover of HMS Audacious to the Royal Navy has been delayed by 17 months due to "technical issues" in its production.
It is reported maintenance is being carried out on four of the 13 Type 23 frigates.
Other issues have challenged the senior service - staff shortages were to blame for HMS Dauntless and HMS Lancaster being docked for months last year.
The Defence Secretary says he wants to improve the availability of vessels.
"When you go the Treasury and ask for more money, the Treasury will turn around and say, 'Well we've given you all this money and they're not working', it makes a harder case when you go for more ships."
It is understood a new system could be followed, where deployed ships are kept in situ and with rotating crews.
New ships are set to be built in the form of the Type 31 frigates, but the first of those vessels are not expected to be in the water until 2023.
Meanwhile, British aircraft carrier HMS Queen Elizabeth is currently taking part in flight trials, although it is not due to be declared operational until next year.