A rally to back the NHS is being held in Barnsley amid fears the poor could be forced to forgo hospital treatment because they cannot afford it.
Tony Wright, for the South West Yorkshire Parthership branch of Unison, said health chiefs fear the new health act could end up sounding the death knell for the NHS.
A leaked government document has revealed there are fears the bill could lead to increased privatisation that would result in paying patients being treated first.
Tony said: "We want Barnsley to join in and show that we do not agree with what's going on and that we shouldn't accept it. We aren't scare-mongering but people should be told what could go wrong.
"Some people just don't realise how this will affect them. It could end up with Barnsley Hospital being run by a private company."
The bill was developed to give more control to clinical commissioning groups who can 'buy' in patient care from companies.
The Save Our NHS rally will start from Churchfields at 10am on Saturday, April 7. There will be speeches from MPs Dan Jarvis and Angela Smith and GP Kailash Chand.
