A former Western Australian police officer has been charged with more than 100 sexual offences, accused of drugging and raping women he met online in a series of alleged crimes dating back to 2010.

WA Sex Assault Squad detectives charged the 50-year-old man from the Perth suburb of Kelmscott following extensive investigations into what they called “predatory sexual behaviour”.

It is alleged that since 2010, the man met numerous women through dating websites and sexually assaulted them during a number of dates.

Police allege a stupefying substance was used against the women at least eight times.

The man faces a total of 108 charges relating to alleged attacks on eight women, including:

• 34 counts of sexual penetration without consent
• 32 counts of aggravated sexual penetration without consent
• Eight counts of aggravated indecent assault
• Eight counts of stupefying someone in order to commit an offence
• Two counts of aggravated assault causing bodily harm
• Three counts of aggravated sexual coercion.

WA Police said they believed other alleged victims were yet to come forward.

The man resigned from the WA Police Force in May 2018 after being charged initially by the Internal Affairs Unit.

He was due to face Perth Magistrates Court on Thursday.

Police said their investigation was ongoing and Sex Assault Squad detectives urged anyone with information to contact police via Crime Stoppers on 1800 333 000.

Women who have concerns they have been a victim of an assault but who do not wish to speak to police can seek support from the Sexual Assault Resource Centre.

-ABC