The Hutchins School covered up the widespread paedophilia of its staff during the 1960s, a former teacher has told a royal commission.

Former Hutchins teacher Geofrey Ayling says he left the prestigious Hobart school after a few years because of the prevalence of paedophilia.

Mr Ayling said that he once heard former headmaster David Lawrence tell a teacher, known as AOC, that he could not be rehired because the board would find out what they were doing.

"It was very clear that they were both in on it together," Mr Ayling told the Royal Commission on Institutional Responses to Child Abuse.

"I was astounded by what they were saying."

Mr Ayling said he knew of six teachers from the school who were believed to be paedophiles, in addition to another two with questionable relationships with students.

He said he did not report the abuse to police for fear of being ostracised, dismissed or sued for defamation.

"I believe there was a conscious decision by the school to cover this up in the 1960s," he said.

Mr Ayling said he raised his concerns with lawyer and former Hutchins student Michael Hodgman, who told him "leave it with me".

Mr Ayling said he was confident Mr Hodgman had put the issue to the board, but did not hear or ask about it again.

Hutchins barrister Neil Clelland, QC, has told the hearing the school now accepts that four students were abused by staff.