TD Ruth Coppinger has held up a thong in the Dáil chamber while challenging judges on what she calls "rape myths".
It follows a rape case in Cork, where the defending barrister held up the woman's underwear in court saying the jury should consider it in its deliberations.
She said the fact she was wearing a lace thong suggested she was open to being with someone.
The accused man was unanimously found not guilty.
While protests are planned on Wednesday over the controversial comments during the trial.
Solidarity TD Ruth Coppinger says "rape myths" need to be seriously examined by the judiciary.
"We've seen recently clothes, fake tan, even contraception being used to discredit women.
"But the last Rape Crisis Network study estimated, at best, 10% ever get reported.
"And only one in 40 rapes have an appropriate punishment.
"How heroic do you have to be, Taosieach - how much levels of fortitude, to pursue a rape trial in this country?".
— Sean Defoe (@SeanDefoe) November 13, 2018
Tweeting afterward, Ms Coppinger said: "In courts victims can have their underwear passed around as evidence and it's within the rules, hence need to display in Dáil."
I hear cameras cut away from me when I displayed this underwear in #Dáil. In courts victims can have their underwear passed around as evidence and it's within the rules, hence need to display in Dáil. Join protests tomorrow. In Dublin it's at Spire, 1pm.#dubw #ThisIsNotConsent pic.twitter.com/DvtaJL61qR
— Ruth Coppinger TD (@RuthCoppingerTD) November 13, 2018