A senior police official said the alleged incident had occurred around 4-5 months ago at the Armed Reserve headquarters in the district.
District Superintendent of Police M S Vijay Kumar told PTI tonight that he ordered a probe immediately after the video came to his notice.
He said the Assistant Sub-Inspector (ASI) was apparently suffering from backache and had requested the home guard to press his back which she did willingly.
"However, it (such act) is not acceptable. A disciplinary action will be taken (against the ASI) based on the inquiry report," Vijay Kumar said.