Evidence that sexual assaults, child abuse, and other human rights violations inside the Australian government's offshore asylum seeker processing and detention centres are being covered up has led one of the country's biggest superannuation funds to dump contractor Transfield Services.

Industry super fund HESTA has sold its stake in Transfield Services citing evidence of human rights violations inside the offshore detention centres run by the sharemarket-listed company.

Industry super fund HESTA has expressed serious concerns about human rights issues on Manus Island. Credit: Nick Moir

The $32 billion fund said the risks associated with Transfield Services, the $597 million company that operates the federal government's detention centres on Manus Island and Nauru, were too high.

"A substantial body of evidence is available pointing to the negative impacts of prolonged mandatory detention of asylum seekers, both the United Nations and the Australian Human Rights Commission are among respected authorities that have said it is a breach of human rights laws," HESTA chief executive Debby Blakey said.