Strip searches of female inmates at the Townsville Women's Correctional Centre were illegal, Queensland ombudsman Phil Clarke has found.

The finding was described as "sickening" by prisoner advocate Debbie Kilroy, who has called for disciplinary action.

Last year, prison guards suspected medicine at the centre was being diverted by a small number of inmates.

In response, they started strip searching women who were receiving the medication.

The searches continued for 10 months until the ombudsman received a complaint earlier this year.

In his investigation, Mr Clarke found the strip searches were inappropriate and the actions were not authorised by head management.

He said the practice broke the law and did not take into account the known potential negative impacts of strip searches on female prisoners.

Mr Clarke recommended more training and a review of strip search procedures.

He recommended a review to ensure any searches at prisons were properly authorised.

Mr Clarke said Attorney-General Jarrod Bleijie had accepted the findings.

Strip searching ‘sexual assault by the state’

Ms Kilroy, from the advocacy group Sisters Inside, said she was disgusted by the revelation and that disciplinary action was warranted.

"It's sickening and the horrifying thing is it's actually not surprising," she said.

"Practices around strip searching women are nothing more than sexual assault by the state.

"Prison officers have been conducting unlawful strip searches of women and so what, the penalty now is training?

"It's just not good enough."