NHS bosses released the first draft of plans for 'Future Fit', the reorganisation of local NHS services, last week.
It suggests patients could be best served by having just one high tech acute treatment centre, supported by a network of smaller urgent care centres around the county.
But campaigners say replacing the two A&E departments at the Princess Royal Hospital in Telford and the Royal Shrewsbury Hospital with the emergency centre will not work in a rural area like Shropshire and bordering Mid Wales.
They claim that under the proposed reorganisation, patients with serious illnesses would face a longer journey before they receive the emergency care they need.
And they say those needing specialist treatment face being sent to regional centres away from their home, including North Staffordshire Hospital at Stoke-on-Trent.
Gill George, chairman of the Shropshire Defend Our NHS campaign, said: "This is really bad news for Shropshire people and for the Welsh residents who depend on the Royal Shrewsbury.
"Our two A&Es get rolled into one, and then on top of that, it gets downgraded. For a lot of people we'll be looking at journey times of three hours or more before they get the specialist treatment they need.
"Centralising specialist care can work in cities, but it needs re-thinking for our large rural area. You can have the best healthcare in the world, but it's of no use to you if you're dead by the time you get there."
Launched in November 2013, the Future Fit programme is examining how health services in the county can best be provided in the future, including hospitals, GPs and community care.
Led by the Shropshire and Telford & Wrekin Clinical Commissioning Groups, it is a partnership programme involving hospitals, patient groups, councils and others.
Future Fit will be finalised next year, but provisional findings suggested one specialised emergency centre that will replace the existing A&E departments in Telford and Shrewsbury, at a location to be decided. It will take the most serious patients.
Meanwhile there could be a return to more community-based and cottage hospitals around the county to serve patients will non life-threatening conditions.
Those behind the Future Fit review say these hospitals would be able to take care of planned care needs and would support the work done by the emergency care centres. There will also be changes to the way long-term conditions are treated. This option will include the care of the elderly and ongoing conditions, and would be based at the community hospitals.