Supporters of a Cornwall hospital may "march on Downing Street" if national cutbacks delay its redevelopment, a charity group says.
A £2.5m refurbishment project is planned for Stratton Community Hospital in Bude.
But the primary care trust believes it could be affected by budget changes.
League of Friends chairwoman Candy Baker said if there were any problems "Downing Street can look forward to some visitors".
Ms Baker said: "It needs improving and refurbishing so it is fit for the 21st Century. I just think it's owed to the people in this area.
"I am concerned that this project may be deferred or cancelled, and, if it is, I don't think it will stop there.
"I think the people of this area will take up the task and do something about it. I think 10 Downing Street can look forward to some visitors."
The Cornwall and Isles of Scilly Primary Care Trust said the project would not be axed but any cuts in capital spending could cause a delay any building work.
Kevin Baber, managing director of the Cornwall and Isles of Scilly Community Health Services, said the PCT was "absolutely committed to delivering the project" and it was "the highest priority."
However, he added: "What we may need to do is review time-scales in light of budget allocations.
"We are waiting for final confirmation of our capital budget for this financial year before we can finalise our time-scales for the project."
He said that initial planning and design and tendering had been carried out and that the trust hoped to started building work as soon as possible.
In the meantime, the league of friends said it was planning to start raising £1m towards the cost in case there were any cuts.