A West Australian police officer has been charged with sex offences against a child.

Police from Internal Affairs say the 48-year-old senior constable is from the Peel district, south of Perth.

He has been charged with eight counts of sexual penetration of a relative, five counts of indecent dealing, procuring a child to engage in sexual behaviour, threat with intent, and attempted sexual penetration of a relative.

It is alleged the offences occurred over a 10-year period from 2001.

The officer has been stood down from duty and will appear in the Rockingham Magistrates Court today.