RIYADH (Reuters) - Saudi Arabia needs to enact a penal code to prevent abuse in its justice system, U.S.-based Human Rights Watch said in a report issued on Tuesday.

Saudi officials say a written penal code is being prepared as part of an overhaul of the judicial system ordered by King Abdullah last year, including expanding the number of courts and judges.

But the legal system, which mainly applies Islamic sharia law, does not recognize precedent.

“Saudi Arabia should urgently enact a penal code to protect all criminal suspects against arbitrary arrest,” the New York-based group said in a statement announcing the publication of two reports based on a year of research and field trips.

“Criminal defendants, especially children, need greater protection against gross abuses during interrogation and unfair trials.”

The reports say defendants often face prolonged solitary confinement, ill-treatment, forced confessions, and are denied a lawyer at crucial stages of interrogation and trial.

Judges often use evidence of reaching puberty as a standard for dealing with teenagers, and in 2007 Saudi Arabia executed three juvenile offenders, including a 15-year-old boy who was only 13 at the time of the crime.

A spokesman for the government-run Human Rights Commission was not available for comment.

Saudi Arabia regularly executes murderers, rapists and drug traffickers, usually by public beheading but judges sometimes given the death sentence to armed robbers and people accused of vague crimes such as “sorcery”.

HRW, which has been given exclusive access to Saudi Arabia over the past year, said the authorities should outlaw the death penalty and all forms of corporal punishment against persons under 18 at the time of the offence.