Saudi Arabia dimmed Friday report that detained activists, including women faced sexual harassment and torture during interrogation as "baseless".
"These recent reports by Amnesty International and Human Rights Watch are baseless," the kingdom said in a statement.
The government said that it "strongly denies" the accusations that are "simply wrong".
The activists, held since May in Dhahban prison on the western Red Sea coast, have faced repeated electrocution and flogging, leaving some of them unable to stand or walk, Amnesty International said on Tuesday, citing three separate testimonies.
At least one activist was made to hang from a ceiling, Amnesty added.
In addition to the torture, at least three women activists also endured "forcible kissing and hugging", Human Rights Watch said in a separate statement also on Tuesday.
The reports came as Saudi Arabia faces intense global criticism over the killing of insider-turned-critic Jamal Khashoggi in its Istanbul consulate on October 2, which tipped the kingdom into one of its worst crises.
More than a dozen activists were arrested in May -- just before the historic lifting of a decades-long ban on women drivers the following month.
Many of them were accused of undermining security and aiding enemies of the state. Some were subsequently released.