Leaked security reports from Manus Island describe frequent self-harm, suicide watch and the use of isolated confinement at the Australian-run detention facility for asylum seekers.

The reports were written by staff from Transfield Services, the company contracted to provide security and catering services on Manus Island.

They report that "major incidents" are happening almost every day at the centre, including fights between detainees, attacks against guards, self-harm and suicide attempts.

The leaked documents are daily security and intelligence reports from July obtained by refugee advocates Humanitarian Research Partners (HRP) and shared with media.

In the most serious case of self-harm reported, a man cut himself with a razor, requiring 20 stitches to his chest and refusing treatment for two long cuts to his head.

The report said the asylum seeker had recently been told he could not voluntarily return to his home country because he was a witness to the killing of Reza Barati in February and had to stay on Manus Island until the investigation was complete.

"Due to this, [he] has been on whisky watch since 26 July," said the report.

Whisky watch is the term used at the centre for monitoring asylum seekers showing mental health problems, and can be every three hours, every 30 minutes or constant observation.

HRP said an average of 14 asylum seekers were placed on whisky watch each day.

On July 21, a man tried to commit suicide and when he was stopped he bit his own arm.

In a separate incident on the same day, an asylum seeker cut himself with a razor.

The reports show that at the end of July there were 18 asylum seekers staying in Australia and six staying in Port Moresby out of the total 1,145 men considered part of the Manus Island detainees.

Several asylum seekers have been transferred to Australia for serious medical treatment, but it is not clear why so many others have been moved off Manus Island.

Human rights group notifies UN of 'harmful practices'

The Transfield Services reports describe how aggressive or "non-compliant" asylum seekers are taken to an isolated area known as Chauka.

Chauka compound is not listed on the official map of the regional processing centre, but HRP said it was located at a different part of the Lombrum navy base, several hundred metres away from the main accommodation.

The group describes Chauka as three shipping containers forming a triangular courtyard covered in shade cloth, with a guard posted at the entry. HRP said each shipping container contained one single bed and nothing else.

"It seems as though part of the purpose of Chauka compound is to encourage more compliant behaviour through the visible punishment of a few key detainees," HRP wrote.

Transfield Services denies the "managed behavioural area" is for solitary confinement.

"The claims in the media are unsupported and deliberately misleading to create a negative public opinion," was a comment in the July 21-22 report.

HRP has written to the UN special envoys for Torture, Human Rights Defenders and the UN Office for Human Rights with concerns about the "use of harmful practices based on fear to manage behaviour".