LONDON - The number of prisoners who killed themselves rose by more than a third last year, the justice ministry said on Tuesday.

There were 92 self-inflicted deaths recorded at prisons in England and Wales in 2007, up from 67 the year before and the highest since 2004, when there were 95.

Prisons Minister Maria Eagle said the government was determined to prevent deaths in custody.

"I sincerely regret this year's increase in self-inflicted deaths after the significant decreases of recent years.

"Our prisons contain large numbers of very vulnerable people, and caring for them is challenging and vital work."

Prison reform groups say the rising levels of self harm are directly related to overcrowding, with the jail population hitting a new high above 81,000 last year.

The government has asked Lord Bradley, a former home office minister, to find ways to keep more offenders with serious mental health problems out of jail and divert them to more appropriate facilities.

The justice ministry said around 130,000 inmates pass through the jail system each year, with 1,500 on any one day assessed as being at risk.

More than 100 prisoners were resuscitated during 2007 after serious incidents of self-harm, it said.

Of the 92 prisoners who took their lives last year, the ministry said 84 were male and 8 female, compared to 64 and 3 respectively in 2006.