The children's minister's described an alleged sexual assault of a boy at a Dublin school as very distressing.

Investigations are underway after the 13 year old reported being assaulted by eight other boys at the King's hospital school last Thursday night.

But there are reports that the child and family agency Tusla was not informed of the alleged incident for four days.

The Children's Minister hasn't ruled out an investigation into the delay in reporting the incident.

Gardai and the child and family agency Tusla have been investigating since Tuesday.

Minister Katherine Zappone: