A maths tutor jailed for sexually and indecently assaulting young students throughout his lengthy career has been charged with a string of further offences after more alleged victims came forward.

Quy Huy "Peter" Hoang, 67, was found guilty last year of molesting four children from three separate families between 2007 and 2014.

It followed a nine-week trial that heard Hoang found "sexual gratification" in young children and used his upstanding reputation in the Vietnamese community to hide the abuse.

Most of the abuse took place in the victims' own homes while parents were in a nearby room.

The evidence presented in Hoang's trial reduced jurors to tears.

Following further investigation, child abuse squad detectives charged Hoang at Silverwater jail with eight more offences on Tuesday.

The charges include sexual intercourse with a child and indecent assault of a child aged under 16.

Police will allege the offences were carried out on five children between 2007 and 2013.

It will be further alleged that three victims - two boys and a girl - were assaulted in their own home while two girls were allegedly abused while studying at a friend's house.

At least two of the five alleged victims were found in more than 100 photographs of children on five mobile phones linked to Hoang.

Hoang is due to face Bankstown Local Court for the fresh charges on Wednesday.

Evidence presented in Hoang's trial last year detailed that Hoang had requested a lock be put on the inside of a door to a bedroom where he taught one of his victims as well as a desk with millimetre-specific measurements.

He claimed he needed privacy, the trial heard.

It would later be alleged in court that these tactics were employed by Hoang to create the perfect environment for his crimes.

The mother of two children Hoang was convicted of assaulting previously said the tutor was seen as a grandfather figure in her family.

She spoke of coming up against a taboo in her Vietnamese community surrounding child sexual abuse but refused to let what happened to her children be swept under the carpet.

She said that people from her community were very superstitious and some families believed their children became victims due to wrongdoings in a previous life, or on their parents' behalf.

"I believe, and this is just my opinion, that it then stops them from reporting the matter and being exposed in order to stop the labelling or finger pointing or whispering in the community," she told Fairfax Media last November.

"They simply don't want to be known as the family that has been tainted or cursed by karma, especially with young girls."