Jailed punk stars Pussy Riot should be freed from prison immediately as their convictions came amid "substantial violations" of Russia's justice laws, according to their attorney.

Three members of the punk collective were jailed for two years in 2012 for performing a protest song against President Vladimir Putin at a Moscow church, with the sentences sparking outrage among stars including Sir Paul MCCartney and Madonna.

One of the trio - Yekaterina Samutsevich - was freed on appeal in October (12) when her sentence was commuted, and now her bandmates Nadezhda Tolokonnikova and Maria Alekhina are also hoping to win their freedom.

Irina Khrunova, a lawyer for the jailed women, has filed an appeal at Moscow City Court demanding officials overturn the punk stars' convictions for hooliganism on the grounds there is no evidence a crime was committed.

She adds, "The rulings in the Pussy Riot case were made with substantial violations of the Criminal Code and the Criminal Procedure Code and should be abolished."

In addition to appealing against their convictions, both women have also applied to be released on maximum parole.

Tolokonnikova is expecting to hear a ruling in her case later this month (Apr13) but Alekhina will have to wait until May (13) for her parole hearing as officials are still waiting to receive all the necessary documents.