There are to be more spot-checks on care homes in England to ensure the safety of the elderly, vulnerable or young people who live in them.
The best homes would be checked less regularly under the new system
New legislation to enable the checks to take place comes into force on Friday.
It will also mean the best performing homes will be inspected less regularly than those with poorer records - which will be checked once a year.
Help the Aged said it would monitor the plan's success, but added it seemed a sensible use of scarce resources.
The regulatory changes follow the launch on 1 March of a centralised vetting and barring scheme aimed at detecting abusers and removing them from the social care workforce.
Care Services Minister Liam Byrne said: "Abusers of vulnerable adults should know that there is nowhere for them to hide in our social care workforce.
"This change is going to free up inspectors to focus a laser-like light on care homes that are performing badly and force them to improve.
"This is what the public asked us to do in our consultation."
Tougher on bad practice
Ministers are also looking at ways to make it easier for relatives of residents to trigger spot checks anonymously.
However care homes with a "consistently" clear record of delivering excellent services will be inspected less regularly.
But they will still be subject to unannounced checks.
Dame Denise Platt, chair of the Commission for Social Care Inspection, said: "People who use social care services tell us they want our inspections to be unannounced, they want to be more involved in telling us what they think of services, and they want us to be tougher on poor services and bad practice.
"These new regulations will help us to be more flexible in targeting our efforts on the services most in need of improvement."
The new legislation is part of a package of changes including the compulsory registration and training of care staff and a £600,000 joint research project with Comic Relief into elder abuse.
Annie Stevenson, a senior policy advisor with Help the Aged, said what the organisation would really like to see was more resources being ploughed into checks for care homes.
But she said that, if that was not going to happen, it was logical to target what resources there were to the poorer-performing homes.
She added: "It's a sensible approach to take and it's an attempt to be a bit more strategic in finding ways of protecting people in care homes."
But Ms Stevenson said the charity wanted to see no let-up in quality assurance in all homes.
"The proof of the pudding will be in the eating, in regard to these changes," she said.