A health official in Papua New Guinea says problems with the water supply at Baisu jail caused an outbreak of disease which is reported to have sparked a mass breakout on Friday.
Mt Hagen Hospital has confirmed that a sixth inmate died in hospital from gunshot wounds sustained after prison guards tried to prevent them escaping.
The Corrections Service had earlier stated that five inmates had been shot dead.
But it could not confirm whether the breakout had been sparked by fears about an outbreak of suspected dysentery at the jail.
The director of Mt Hagen Hospital Michael Dokup says two or three prisoners died in the prison last month after suffering from an as yet unconfirmed disease, while about 12 have been treated in hospital.
"During the last few months the prison has had problems with water. Clear water from the town could not get into the prison, the prison is about a good twenty kilometres out from town so the prison does not have any good clean water, that's why most of the prisoners have gone sick especially with diarrheal diseases."
Dr Dokup says health authorities are inspecting the jail and producing a report on its conditions.