Paul Skillen, who worked as a G4S security supervisor at the centre, emailed colleagues in November expressing concerns that poorly trained workers were manning the facility, which was “a tinderbox ready to ignite”.

The emails have been submitted to a Senate inquiry set up to investigate events at the centre in February, which left 62 asylum seekers injured, one with gun-shot wounds.

Reza Barati, a 23-year-old Iranian asylum seeker, was killed by multiple blows to his head during the violent confrontations.

In his emails, Mr Skillen warned that local Papua New Guinea workers were being assigned to high-risk roles with no experience and limited training.

He said the entire structure of the incident response team was not working and needed revision.

“I understand there are some plans afoot, however, I feel the centre is currently a tinderbox ready to ignite,” he wrote.

“The intelligence being received at the moment, I am led to understand, supports my thoughts.

“In the event that the tinderbox ignites, the centre will be totally unprepared, and members of the IRT and other staff will undoubtedly get hurt, some badly.”

Mr Skillen said questions about the consistency of the training and leadership “leaves both G4S as a company, and the individuals concerned, liable should anything untoward occur".

On Friday, a spokesman for G4S said the company refuted the allegations in the emails “and we will be addressing them in our submission to the Senate inquiry”.

In a second email that was part of his submission, Mr Skillen wrote that basic crime-scene preservation measures were not in force at the facility after a hanging attempt in one of the compounds.

He described having to remove evidence in plastic garbage bags and said there was no control over who entered and handled items in an area that was potentially a crime scene.

There was also no means of documenting evidence besides “a scrap piece of paper”.

“We also need to locate a secure area to store any potential evidence, somewhere big enough for numerous items, and secure enough that only certain staff [maybe duty ops managers] have a key,” he said.

“If we are unlucky enough to have a death in custody, we may all end up before a PNG coroner, and these simple steps would assist us and the PNG constabulary greatly.”

In a separate submission, one of the architects of Australia’s offshore processing regime said he was concerned Australia was not protecting the human rights of asylum seekers.

Foundation House chief executive Paris Aristotle wrote that “the current government has not resiled from the recommendation that the treatment of people transferred to PNG should be treated in accordance with international human rights standards.”

“Reports from UNHCR [the United Nations High Commissioner for Refugees] and other sources indicate strong concerns that the recommendation has not been comprehensively and properly implemented,” he said.

The submission cites a UNHCR report which found the legal framework and physical conditions for the detention of asylum seekers was below international standards and neither safe nor humane.

Earlier this month, it was revealed the Abbott government was not planning to release the interim report of its inquiry into the violent clashes.

Immigration Minister Scott Morrison did not respond to specific questions about Mr Skillen's submission.

A spokeswoman for Mr Morrison said in a statement the government was assisting Papua New Guinea in finalising its police investigations.

“Ministers agreed that all relevant information from the independent administrative reviews would be handed over to the police investigation to enable swift prosecutions," she said.

“The outcomes of the investigations will inform a coronial inquiry in PNG.

“In addition, both governments will expedite the implementation of recommendations arising from the investigations."

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