A House of Commons committee has called for more training and guidance on the use of Personal Information Notices (PINs) by police.
The Home Affairs Select Committee has recognised there is a "clear danger" that PINs can be used inappropriately.
The committee, chaired by MP Keith Vaz, made the call in a report published last week.
It has urged its successor committee, which will be formed after the General Election, to monitor progress to see if improvements have been made.
PINs are issued by the police under the Protection from Harassment Act 1997, and have no legal force. They warn recipients that a complaint of harassment has been made about them, and that they could be arrested if another complaint is received.
The Metropolitan Police in Croydon issued Croydon Advertiser chief reporter Gareth Davies with one last year – and recently rejected his complaint about their actions.
The commitee's report said: "PINs can be a useful tool for stopping harassment, meeting the needs of the victim and addressing problematic behaviour.
"However, there is a clear danger that they may be used inappropriately if they are not done in conjunction with good risk assessment and sufficient investigation.
"It is vital that police forces provide further guidance and training to officers on the appropriate use of PINs, highlighting in particular that the use of a PIN is generally not appropriate where an investigation has established evidence of a course of conduct.
"Remedial courses should also be given to police officers who have used PINs inappropriately. The ACPO and College of Policing review of practice advice should take these issues into account.
"We hope that our successor Committee will monitor the issue of PINs to assess whether these improvements take place."
Cleland Thom is author of Internet law for journalists