The Vancouver Police Department says the member with 10 years' experience was arrested Friday night by Mounties in Maple Ridge, B.C.
They say a woman went to the Ridge Meadows detachment earlier that day and reported the allegations.
Vancouver police say they were advised and then notified the province's police watchdog.
The officer has been removed from front-line duties, pending the results of an investigation.
His identity has not been released, and Vancouver police say the RCMP is in charge of the investigation.