Cheltenham General Hospital's emergency unit is to be downgraded from September, MP Alex Chalk has said.
In a public statement, the MP said he was "astonished and dismayed" with the move.
Gloucestershire Hospitals NHS Foundation Trust has said no decision has been made.
But Mr Chalk said: "For it to be happening in the month of August when everyone is away seems to be really cynical."
The trust said in a statement that it will hold an "open discussion" with the community on any future changes.
"When launched, this will very much be a process of engagement," it said.
"We really want to hear what people think about how services could be provided in the future and have a genuine and open discussion about this."
A range of potential solutions will be set out in a public discussion document, the trust added.