A report published by a group of MPs says "poor communication" between the UK and Welsh Governments has led to issues of gang violence in Welsh prisons.
The Welsh Affairs Committee also found "lack of collaboration" led to issues of inadequate healthcare and insufficient provisions for prisoners in Wales.
Responsibility for Welsh prisons is divided between the Welsh and UK Governments.
While Westminster holds overall responsibility for the criminal justice system, the Welsh Government provides services like healthcare and education in those prisons.
Commenting on the report, David T.C Davies who chairs the committee said:
Based on the findings, the group of MPs have made a number of recommendations, including:
- Improving collaboration between the Governments to better deliver healthcare for offenders.
- Adequate funding for probation arrangements in Wales.
- Improving living conditions in crowded Welsh prisons and providing activity spaces.
- Installing security scanners to reduce illicit activity including the smuggling in of drugs and mobile phones.
In response to the report and its recommendations, the Ministry of Justice said it meets regularly with the Welsh Government. A spokesperson added that they had:
"Worked together on strategies to improve learning and skills in prison, health services, and offender rehabilitation".
Meanwhile the Welsh Government said:
"While justice policy is a non-devolved matter, we recognise the need to work with the Ministry of Justice across the areas that we are responsible for in order to improve prisons in Wales".
The Welsh Affairs Select Committee also called for women's residential centres to be established in north and south Wales. As it stands there are no women's prisons in Wales.
MPs stressed that any new prisons in Wales should be equipped "to service primarily the needs of Welsh prisoners" as opposed to being an "overspill facility" to English prisoners.