A northern beaches man charged with 31 child sex offences is facing a further four charges after a ninth alleged victim complained.

Kyle Daniels, 20, was charged last month with the sexual abuse of an eight-year-old and a six-year-old while teaching them to swim at a Mosman pool. A further six girls, all under the age of 10, then subsequently came forward with claims of sexual abuse at the Mosman Swim Centre.

Kyle Daniels, right, who is accused of sexually assaulting children he was teaching to swim. Credit:Facebook

On Thursday, police laid four further charges against Mr Daniels; four counts of sexual intercourse with a child under 10.

The Knox graduate is now facing 35 charges relating to nine alleged victims, including 12 counts of sexual intercourse with a child under 10, six counts of intentionally sexually touching a child under 10 and 14 counts of indecently assaulting a person under 16.