Existing care homes will not have to meet the same requirements as new homes for room sizes, ramps, lifts and bathing facilities it was proposed this week.
Rules requiring homes to meet minimum standards by 2007 were brought in for both existing and new homes in April under the Care Homes Regulations 2001.
But that policy will be reversed if the proposals put forward in Care homes for older and younger adults are rubber-stamped after a 12-week consultation period.
'The hard core of providers who've let the sector down over many years by delivering poor standards may take comfort, sit back and then do nothing to bring their facilities up to a decent standard,' she said.
'The many excellent care providers who are making great efforts to upgrade their facilities may feel undermined.'
But Ms Parker added that the commission 'would not hesitate to act' if service providers deliver poor services.
The Department of Health said the change was the result of a determination not to 'impose physical or environmental requirements that would cause homes providing good quality care to close down'.