A 23-year-old Northern Beaches man, already charged with the alleged "sextortion" of one teenager, will be charged on Wednesday with 65 new offences relating to the alleged sexual exploitation of another 35 child victims.

Kurtis Whaley, from Manly Vale, was arrested by the Australian Federal Police in February this year, after he allegedly lied online about his age and identity to elicit sexually explicit photos from a teenager under the age of 16.

Police allege he then threatened to share the images with the teen’s friends and family if they refused to send more explicit material, prompting them to tell their parents, who alerted police.

Mr Whaley has been in police custody since he was arrested at Sydney International Airport on February 21 and charged with five offences.

On Wednesday he will face Sydney Central Local Court to be charged with another 65 offences, including multiple counts of both soliciting and transmitting child pornography and 32 counts of producing child abuse material.