"We have had enough scandals over the last 10 years to totally alarm us about the quality of medical care in some cases," said spokeswoman Sheila O'Connor.
The announcement of the new checks on doctors has been made in advance of the publication of the report of the inquiry into the practice of controversial Drogheda obstetrician Dr Michael Neary.
The report, due to be published next week, is expected to make a number of recommendations in terms of clinical audit, peer review, training and "whistle blowing" by staff who feel there may be something amiss with practices in a hospital.
IMC president Dr John Hillery said that while most doctors were willing to take part in the random assessments, it could not compel everyone to participate under current laws.
But, he said, the council believed it had waited too long for supportive legislation and had now decided to roll out its own competence assurance structures this summer.
The new assessment system will involve patients and medical and non-medical colleagues of the doctor filling in questionnaires, in confidence, about the doctor's performance, with a summary of the findings sent to both the doctor concerned and the council. As part of the investigation, lay and medical assessors will observe doctors at work.
Ms O'Connor said Patient Focus were pleased that the doctors' assessment system was being introduced but were disappointed that it was being done on a voluntary basis.
"There will be no way of most patients knowing if a doctor has complied with it and are up to scratch. While most will take part, there will be some who won't," she said.
Irish Medical Organisation president Mr Asam Ishtiaq said they would welcome any initiative from the IMC to improve the quality of care being provided to patients and would encourage doctors to take part.
The Irish Hospital Consultants Association also welcomed the competence assurance procedures but said there were related funding and contractual issues that must be addressed by the Health Service Executive.