It took twenty years of requests for an elite Hobart school to apologise to a student who was sexually abused by its headmaster in the 1960s, a Royal Commission has been told.

Sitting in Tasmania for the first time, the Royal Commission into Institutional Responses to Child Sexual Abuse was told the Hutchins School initially denied of a former student's plea for an apology.

The former student, known as AOA, was sexually abused by former headmaster David Ralph Lawrence, and maintained contact with him after leaving the school and the state, counsel assisting the commisssion Angus Stewart, SC, said.

Mr Stewart said the school had only apologised to AOA last month, despite reporting the abuse in 1993, as well as media reports and the assistance of federal MPs.

In 2002, then headmaster William Toppin wrote to AOA, telling him that the school had no knowledge of his complaints.

"The curent school community (does) not consider itself accountable for the unfortunate events," the letter said.

Mr Lawrence worked at the school between 1960 until he suddenly resigned in 1970.

The school's lawyer Neil Clelland, QC, said the school accepted it had taken too long to apologise to AOA.

Mr Clelland said the school accepted that the four abuse complainants had been truthful.

"I am instructed that the the current board wishes to apologise for the hurt and distressed caused to each of them," he said.

Mr Stewart said the commission will hear evidence of abuse by Mr Lawrence, as well as former French teacher Lyndon Hickman.

Mr Toppin and current headmaster Warwick Dean are expected to give evidence before the commission.