Peter Harris, who has been living in Thailand and had worked on making schools in the country sustainable under a federal government grant, was arrested at Melbourne Airport on Tuesday.

The 78-year-old ex-principal was attempting to board a flight when he was arrested, a police spokeswoman confirmed.

Dr Harris faces five charges, including assaults in East Melbourne, Maryborough and Castlemaine between 1975 and 1983.

He was founding principal of Billanook College in Mooroolbark in Melbourne's outer-east, which opened in 1980, and left in 1996.

Prior to that he was founding principal at Maryborough Christian Community College, now known as Highview College, which opened in 1974.

Dr Harris was also a teacher at prestigious Melbourne private school Haileybury College in Keysborough from 1967 until 1973. He was a commerce teacher, librarian, hockey coach and boarding house master.

The alleged abuse relates to two incidents in Maryborough, one in Castlemaine and one in East Melbourne, a police spokesman said.

The charges include gross indecency with a male, indecent assault and knowingly possessing child abuse material.

Dr Harris was bailed to appear at Bendigo Magistrates Court next Tuesday.

The Department of Foreign Affairs and Trade gave Dr Harris grants of more than $20,000 towards his work helping Thai schools become more sustainable.

"In 2011, the former Australia-Thailand Institute (ATI) provided two grants to Dr Peter Harris of Global Entrepreneurial Education totalling $22,500," a DFAT spokeswoman said.

An online biography says he was born in the United Kingdom and moved to Australia with family before heading to Phuket in 2008.

He was also vice-president of a Rotary club at Patong Beach in more recent years, but is now believed to have left.

Highview College principal Melinda Scash said she was aware the man charged may have been a staff member at the time of some of the alleged abuse.

"It is possible that this person was formerly a staff member of Highview College during this period of time," she said in a statement.

"Highview College is a child-safe environment with a zero tolerance for any form of child sexual abuse. We ask that anyone with further information or concerns contact Victoria Police directly.

"With the matter being investigated by the police we will not be making any further comment.

"However, we can reiterate that Highview College continually reviews its child-safe processes and procedures, and provides ongoing staff training with an absolute focus on providing the highest standard of safety, care and compassion for our students."

In a now-deleted blog post about Dr Harris, Haileybury College had described the former teacher as "lively and dynamic".

"As well as teaching economics, he coached the Hockey XI Team, was a boarding house master, an officer in the cadet corps and chief librarian in 1973," the post says, according to an archived version of the website.

"He was very popular with the students who called him 'Lightbulb' because his face would light up dramatically when anything new or interesting occurred."

Uniting Church Australia Synod of Victoria and Tasmania general secretary Mark Lawrence said the church was not aware of the allegations.

"As it is a police matter it is inappropriate to make further comment. To the best of our knowledge, Peter Harris has no formal connection with the Church.

"The Uniting Church sees any abuse of children or vulnerable people as abhorrent and is committed to their safety."

Billanook and Haileybury colleges declined to comment.

If you or anyone you know needs support, you can contact the National Sexual Assault, Domestic and Family Violence Counselling Service on 1800RESPECT (1800 737 732).

The Age

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