A new multi-million pound prison extension will allow more Welsh inmates to serve their sentence in Wales, says the Welsh secretary.
Cheryl Gillan opened the development at Parc Prison, Bridgend, which will add 320 prison spaces with capacity to increase to 470 by mid 2011.
"[It] goes a considerable way in addressing the shortfall in custodial provision in south Wales," she said.
The upgrade would make Parc one of the UK's largest prisons, she added.
The development provides Parc, the only privately-run prison in Wales, with a new medical centre, new staff training centre, catering facilities and expanded car park for visitors and staff.
Mrs Gillan said: "It is very important that Welsh offenders, wherever possible, serve their sentences in Wales and this extension will make it possible for this to happen.
"Maintaining contact with their families and, keeping a link with their communities, plays an important role in effective rehabilitation.
"Parc Prison has a proud record on the innovative projects it has developed to ensure a better and more trusting relationship with offender families and the local community."
The Welsh secretary was joined at the event by UK Prisons Minister Crispin Blunt, who said that the development would boost the local economy by delivering extra jobs.
Mr Blunt said the UK government was investing more than £100m a year in front-line offender management services in Wales using a mixture of public, private and voluntary sector providers.
The aim was to change behaviours in offenders in custody, he added.
"New places, such as those here at Parc, mean we can provide decent, efficient prisons which give good value to the taxpayer," said Mr Blunt.