An Egyptian Muslim prayer leader has been ordered to remain in Australia after pleading guilty to three charges of indecent assault on Sydney's northern beaches.

Ahmed El-Kahly is accused of approaching two 16-year-old girls and a 57-year-old woman at Dee Why, in separate incidents.

Police allege he touched the breasts of two of the victims.

The older woman was walking her baby grandson in a pram at the time.

El-Kahly is in Sydney for Ramadan on a short stay visa and was planning to return to Egypt this week.

He will be sentenced at a later date.

Prosecutors say there could be further charges.