Residents in West Sussex are being urged to go online and sign a petition in the fight to save hospital services.
Campaigners say plans will create an "A&E desert" in central Sussex
The e-petition was launched by the county council and has been signed by many councillors and local MPs.
The West Sussex Primary Care Trust Fit for the Future proposals could lead to the downgrading of services at two out of three hospitals in the county.
St Richard's at Chichester, Worthing and Southlands, and the Princess Royal, Haywards Heath, risk losing A&E units.
The primary care trust (PCT) wants only one hospital in the county to have the full range of A&E, emergency surgery and consultant-led maternity services.
Health bosses have said that under the proposals the remaining A&E service would be "souped-up" and more paramedics would be on hand to treat patients at the scene of an accident.
It has also outlined its plans for a series of urgent care centres that would deal with less serious injuries.
The Fight for the Future petition calls for the government to instruct the trust to come forward with "acceptable options for health service provision which better reflect the needs and concerns of residents".
'United we stand'
County council leader Henry Smith said: "I would urge everyone who shares our concern to go online and join our fight to save hospital services in the county.
"Our stance is clear, downgrading is not an option for any of our hospitals.
"As the saying goes: united we stand, divided we fall."
The petition will be presented to the health secretary and the PCT.
Residents who do not have internet access can sign the petition at their local library.