Police say the 89-year-old abused four boys, then aged between 10 and 11, while working as a teacher at a school in Lilyfield, in Sydney's inner west.

The alleged abuse occurred in the late 1960s.

Police have been investigating accusations of sexual and indecent assault at the school since December 2019.

The 89-year-old was charged on Thursday with 13 counts of assault male and commit act of indecency, and three counts of buggery.

He will face Blacktown Local Court on Monday.

Australian Associated Press