Dyfed-Powys Police have been issued a warning that they could be putting public safety at risk by failing to record thousands of crimes a year.
Dyfed-Powys Police has been issued with an "accelerated cause of concern" by Her Majesty's Inspectorate of Constabulary and Fire and Rescue Services (HMICFRS) due to missing out on an estimated 4,400 crimes every 12 months.
On Friday, the watchdog revealed the force was only recording 87.6% of all reported crime, and only 85.4% of violent crime - some of which involved domestic abuse or vulnerable victims.
HM Inspector of Constabulary, Wendy Williams, said she was "concerned that Dyfed-Powys Police has consistently failed to record so many crimes and is risking public safety."
Dyfed-Powys Police said it accepts the recommendations made by the HMICFRS and "has plans in place to improve its crime recording".
The report found "minimal evidence of crime recording being effectively supervised" by officers. This would inhibit the force's ability to make sure a victim is safeguarded and an appropriate investigation is completed.
This latest inspection also found the force's level of crime-recording was broadly unchanged since the previous inspection in 2018 - suggesting a failure to make improvements.
HMICFRS has now made a number of recommendations for Dyfed-Powys Police, including improving its systems and processes for recording reported crimes, paying particular attention to domestic abuse cases.
It also recommended ensuring adequate supervision of the crime-recording decisions made by officers and staff.
Another recommendation is that the force should provide better training for all its officers within the next three months.
HM Inspector of Constabulary, Wendy Williams, said: "Anyone who reports a crime should feel safe in the knowledge that their local police force will record it. I am concerned that Dyfed-Powys Police has consistently failed to record so many crimes and is risking public safety.
"I am particularly worried that victims of domestic abuse are being let down by Dyfed-Powys Police. Failing to record these crimes often results in vulnerable victims not being safeguarded properly and no investigation taking place.
"We told Dyfed-Powys Police to make improvements in crime recording two and a half years ago, yet it has still not made any progress.
"The people of Wales will rightly expect Dyfed-Powys Police to ensure their reports of crime are recorded, reported and taken seriously. We will therefore be closely monitoring the force's performance to make sure that public safety comes first."
The force has been issued with a "cause of concern" which means its progress will be closely monitored by the inspectorate with the potential for further action.
Dyfed-Powys Police chief constable Claire Parmenter said: "We accept the concerns and recommendations published by HMICFRS in respect of crime data integrity. As an organisation, we are firmly committed to supporting victims and putting them at the heart of everything we do.
"The force has plans in place to improve its crime recording and I am determined we will get this right."