A task force is to examine possible changes to health services, including hospital A&E care, in West Sussex.
Campaigners fear the hospital could become a "local general hospital"
The Health Scrutiny Select Committee, set up by West Sussex County Council, will look at Worthing Hospital and St Richard's Hospital in Chichester.
Changes reportedly being considered include downgrading A&E facilities and reductions in other services.
Committee chairman, Anne Marie Morris, said the aim was to try to ensure the best possible outcome for everyone.
She said issues the committee would be looking at would include community care and transport needs and the effects of moving some hospital-based acute care into the community.
Andrew Tyrie, the Conservative MP for Chichester, has urged his constituents to fight for St Richard's Hospital.
Last week, campaigners sent thousands of leaflets to homes and shops highlighting possible cuts.
Four other Conservative MPs have also set up a campaign aiming to protect Worthing Hospital from any cutbacks.
Peter Bottomley (West Worthing), Nick Herbert (Arundel and South Downs), Nick Gibb (Bognor Regis and Littlehampton) and Tim Loughton (East Worthing and Shoreham) claim the Surrey and Sussex Strategic Health Authority (SHA) is under severe financial pressures and frontline services could be at risk
They have set up an online petition and hope to get thousands of signatures in support of their initiative.
The council committee was told on Monday that the SHA, which now comes under NHS South East Coast, has to tackle a £35m overspend in West Sussex.