Police stop and search powers in England and Wales are to be overhauled with a revised code of conduct, Home Secretary Theresa May has said.
She told MPs an inquiry had found 27% of searches may have been illegal.
She said that if the number of stop and searches did not now come down, she would seek to change the law.
The move follows a consultation, which highlighted concerns that stop and search was used too widely and was unfairly targeting ethnic minorities.
Labour say the plans do not go far enough.
‘Affront to justice’
Recent figures show only about 10% of more than a million searches lead to an arrest, with black people six times more likely to be stopped than those who are white.