It comes as confidence in policing and the criminal justice system continued to decline across the two nations.
StopWatch, which advocates for fair and accountable policing, said there is a "growing disillusionment with the police" and questioned whether the service is still "fit for purpose".
Figures from the Office for National Statistics show only 39% the 527 people aged 16 and over surveyed in Gwent in the year to March said the police force does "an excellent or good job".
It was the lowest rate in England and Wales.
And it was down slightly from 41% the previous year, and from 46% five years earlier in 2019-20.
Across England and Wales, just 49% of the 28,896 survey respondents said they believe the police do "an excellent or good job" in 2024-25.
This figure has been declining since comparable records began in 2011-12, when it stood at 62%.
Meanwhile, national victim satisfaction with how police handle crime dropped to a historical low.
Just 51% of respondents who had been a victim of crime in the recent year said they were either very or fairly satisfied with how the police handled the matter.
This was down from 55% in the previous year and is the lowest figure since this question was first asked in 1992.
StopWatch executive director Habib Kadiri said: "The survey results tally with anecdotal evidence from overpoliced and under protected communities, which suggests a growing disillusionment with the police.
"People increasingly sense that they do more harm than good.
"The tragedy of this is that while many members of the public believe in the police as an institution and want them to do better, the chronic inability of forces to provide a satisfactory service raises the question: is it fit for purpose anymore?"
Network for Police Monitoring campaigns and media coordinator Kevin Blowe cautioned the survey results should be examined alongside complaints data, which he said usually shows "poor service following the report of a crime and then the use of police powers".
He added: "Even though the number of police officers is higher now than it was in 2011, the Westminster consensus remains 'more officers' and 'more visibility' as solutions to this issue, but never more resources for alternatives in local communities that might genuinely make people feel safer.
"If any other public service failed as badly as policing, we would already have started a debate about replacing it with something better."
Last Wednesday, the Home Office said every community across England and Wales has been assigned a "named, contactable" officer to handle reports of crimes like anti-social behaviour.
The move comes to boost police visibility in town centres and ensure the public has "consistent direct links" to their local force.
The figures also show 46% of those surveyed in Gwent agreed with the fact that the local force does "deal with local concerns".
It was in line with the average across England and Wales.
National Police Chiefs’ Council chair Chief Constable Gavin Stephens said police leaders "acknowledge that over recent years there has been a decrease in confidence in policing", but added they are "working hard to change this".
He said: "A decade of underinvestment has left police forces with insufficient resource to meet public expectations, alongside complex and changing criminality, degraded facilities, systems and technology, and restrictions on the type of workforce.
"These are elements that need to be addressed urgently for the service, and this is why the Government’s programme of Police Reform must be a priority and must be ambitious."
He said the NPCC is working on improving trust in policing, and called on the Government to continue increasing investment in policing and "commit to ambitious reform".
A Home Office spokesperson said: "Neighbourhood policing has been decimated since 2010, taking officers away from being out on the beat where they build relationships, trust and safety within communities.
"That is why, through our Neighbourhood Policing Guarantee, this Government is restoring visible policing in every area, deterring and preventing crime.
"Every neighbourhood across England and Wales now has a named, contactable officer in place to respond to local concerns, and we are rolling out the first 3,000 new neighbourhood officers and PCSOs who will be on the streets by March next year."