The Ontario Health Coalition said taking such things as diagnostic services, physiotherapy and operations like cataract surgeries out of hospitals and having them provided by private clinics is a direct threat to publicly-funded medicare.
"This is a giant step towards American-style private health care, there's no question," said coalition executive director Natalie Mehra.
"Virtually all of the private clinics that exist in Canada bill the public health system and they charge extra user fees too. That's illegal under the Canada Health Act, but that's routine in the private clinics."
Patients going to private clinics in Ontario can be billed up to $1,300 in extra fees for cataract surgery, while people looking for endoscopies or colonoscopies face fees of $80 to $200 above what's billed to OHIP, said Mehra.
"These are services patients have paid for already through our taxes, and the private clinics are bringing in two-tier health care," she said. "The Ministry of Health has turned a blind eye to these charges, and is now expanding the private clinic sector."
Health Minister Deb Matthews was unavailable for comment Monday, but her office said the government was committed to "move more routine, low-risk procedures into the community" through non-profit clinics.
"We know that this reform is good for patients, will provide better value for taxpayers and will ensure that patients receive the right care in the right place at the right time," said press secretary Samantha Grant.
"We will only move these procedures into not-for profit clinics and all medically necessary procedures performed in these clinics will be covered by OHIP."
The ministry said clinics will be required to make patients aware of any fees for uninsured services, and that those fees are optional.
The giant Unifor union is supporting the health coalition's effort to stop the expansion of private clinics, pointing to reports of quality control issues at some clinics, and said the government's move won't necessarily save taxpayers any money.
"They'll try to convince people that this is good, that they'll maybe even save money moving these services out of the hospitals, but I would ask at what expense," said Unifor's Katha Fortier. "Privatized clinics obviously don't have the same quality control, they don't have the accountability of a board that lives in the community and they don't have an accreditation system."
The health coalition said people want local hospitals that provide a wide range of services, and warned the government's plan will put even more pressure on the public system by allowing the private clinics to siphon off medical staff and deal only with the healthiest patients.
"Local hospitals will lose funding and scarce specialists and nurses to private clinics, but will be left with the heaviest care patients that the private clinics don't want because those patients are not profitable," said Mehra.
"It is the opposite of a community hospital where patients can get publicly-funded health care in one place, close to home."
The Liberals never brought the issue of expanding the role of private clinics to a vote in the legislature, and never raised it during the last election campaign, said Mehra.
"In our view, there is no mandate whatsoever for this provincial government to embark on a radically different approach that would dismantle the idea of a community hospital that provides a relatively comprehensive range of services and fragment that out into a number of private clinics," she said.
"We think it's wrong for the government to, behind closed doors, make these radical policy decisions."
The coalition will hold a referendum April 5 with a goal of getting 50,000 people to vote against the decision to move hospital services to private clinics.
Volunteers with ballot boxes will be in stores, cafes and restaurants while others will knock on doors across the province to enlist support. They will focus their efforts in Windsor, London, Kitchener, Peterborough and Sudbury, but people across Ontario are encouraged to vote to show the Liberals they want local hospitals protected.
Follow @CPnewsboy on Twitter