The Association of Community Health Councils has already tried to get a judicial review of the decision, but dropped the action after Mr Milburn refused to fund it.
Ministers intend to scrap Community Health Councils, but a prominent Labour MP says they have made a mistake and should think again.
David Hinchliffe MP has written to Health Secretary Alan Milburn asking him not to replace CHCs with Patient Advocacy and Liaison Services (Pals).
Community Health Councils are independent bodies which act as patient representatives, advising them and mounting inspections of casualty departments and wards.
The councils have waged a vigorous campaign against their abolition, saying that the new patient representatives are not sufficiently independent from hospital management to do the job properly.
Mr Hinchliffe, chairman of the House of Commons Health Select Committee, told Mr Milburn that the new advocates would do little to address the "democratic deficit" in the NHS complaints procedure.
He said: "I feel that what is currently being proposed will not address the genuine worries of patients and their representatives over the current complaints system.
"While there are many positives in the NHS plan, I believe that the alternative proposed to the current CHC system does not offer a coherent response to current anxieties."
The Association of Community Health Councils has already tried to get a judicial review of the decision, but dropped the action after Mr Milburn refused to fund it.
Donna Covey, from the association, said: "There is a clear consensus on this issue across the health community, from patient organisations to professional bodies.
"The NHS needs an effective, independent watchdog. We welcome greater public involvement in the NHS, but it is no substitute for independent scrutiny.
"Getting rid of CHCs won't get rid of the problems in the NHS, but it might just make them more difficult to detect."
Approximately 700 people work full-time for the CHCs across the country - with 5,000 as unpaid volunteers.
Created in 1974, CHCs helped to uncover the Rodney Ledward gynaecological surgery scandal in Kent.
Health Minister Gisela Stuart defended the changes, claiming CHCs were out of date, undemocratic and covered too many different roles. Splitting up these roles, she told Radio 4's Today programme, would benefit patients.
She said: "The system does need to be simplified. That is why the new patient and advocacy liaison services will be located in every Trust.
"It makes it much clearer for the patients where is the first point of call to get answers and get direct access to the chief executive for example."
She added: "To explain the system may make it sound more intricate but for a patient there will be a direct line into getting answers and taking complaints forward at every point where they use the NHS."