CARACAS (Reuters) - A Venezuelan rights group says at least 41 inmates died in suspicious conditions last week, more than three times the official death toll authorities have blamed on overdoses.

The government said last week 13 inmates died after breaking into the infirmary ward of the David Viloria penitentiary center in the western state of Lara and gorging on medical products including alcohol and antibiotics.

But local rights group Venezuelan Observatory of Prisons questions that official version.

A handful of relatives claim the prisoners, who had reportedly kicked off a hunger strike to protest their living conditions, were poisoned, according to preliminary testimonies the group collected.

"The (inmates) were sent bottles of water and food... they haven't said who sent it, but it was let into the prison and that's what family members say caused (the intoxications)," said the group's Humberto Prado, who called for independent toxicological exams.

There was no independent confirmation of the death toll or allegations of poisoning. Requests for comments from the government went unanswered.

At least 200 inmates were intoxicated at the prison, according to Prado, who says the facility designed for roughly 850 inmates was housing around 3,700.

The incident puts the spotlight back on the South American country's notoriously turbulent prisons, where riots, weapons and drugs are widespread.

A bloody riot at that same prison last year claimed over 50 lives.

"This latest incident is atrocious but it is nothing new," Prado said.

Human Rights Watch on Monday called for "prompt, thorough, and impartial investigations" into the incident and lamented what it said were thousands of deaths in Venezuelan jails in recent years.

(Reporting by Alexandra Ulmer; Editing by Lisa Shumaker)