"The prolongation of their incarceration in the conditions of jail seems to me to be unproductive," Medvedev told the giant pro-Kremlin United Russia political party of President Vladimir Putin during a meeting in Penza, about 390 miles southeast of Moscow.
"A suspended sentence, taking into account time they have already spent, would be entirely sufficient," he said in remarks shown on state TV and quoted by the non-governmental Interfax news agency.
"Imprisonment is a very severe -- I would even say a frightening -- responsibility," Medvedev told party members. "What has already happened -- that this well-known group of girls has been in prison quite a long time -- is a very, very serious punishment for everything they did, regardless of the sentence."
So the six months the women already served is "fully enough to make them think about what happened, because of their stupidity or for some other reasons," he said.
Medvedev, a lawyer by training, added it did not wish to "take the judge's place" with his comments.
The women -- including two with young children -- have been in jail since they were arrested in early March.
Medvedev, Russia's president from 2008 until May, also stressed to party members he did not approve of the women's Feb. 21 anti-Putin stunt inside Moscow's landmark Russian Orthodox Cathedral of Christ the Savior a few blocks from the Kremlin, saying that even thinking about it made him nauseated.
"I am sick over what they did, of their public appeal and the hysteria that surrounds them," he said.
But the three women -- Maria Alyokhina, Yekaterina Samutsevich and Nadezhda Tolokonnikova -- have "been in jail long enough," he said.
The women were sentenced to two years in prison Aug. 17 after being convicted of hooliganism motivated by religious hatred.
Their performance was part of a large protest movement existing at the time against Putin's re-election.
The women -- known for staging unannounced provocative performances about Russian political life in unusual and unauthorized locations -- removed their winter clothing, pulled their trademark colorful ski masks down over their faces, walked toward the altar, crossed themselves, bowed and began a performance.
They were escorted from the cathedral by guards after less than a minute. Footage of the performance, including their removal, was included in a music video titled "Punk Prayer: Mother of God Drive Putin Away," posted on YouTube.
In the video, they call on the Virgin Mary to "become a feminist" and get rid of Putin.
The son also uses crude language to attack Putin and Moscow church Patriarch Kirill I.
During the trial, Putin called for the women not to be judged "too harshly."
The maximum sentence was seven years. Prosecutors had asked for three years.
The women remain in a Moscow pretrial detention center ahead of their appeal, due to start Oct. 1.
The United States and many other Western countries condemned the sentence as disproportionately severe.
Pussy Riot attorney Nikolai Polozov told Kommersant FM news radio late Wednesday he thought Medvedev's remarks might mean Moscow wanted simply to be done with the case.
"In the end the authorities got themselves caught in a trap," he said. "The international community gives an unambiguous assessment of this case, and Russia's reputation is rapidly falling, and the authorities are trying to find some solution so that they can emerge from this episode with a pretty face."