Yekaterina Samutsevich, 30, who has been released with a suspended sentence while her two band mates are to serve two-year prison terms, filed the complaint with the Strasbourg-based body, her lawyer Yelena Khrunova told Kommersant daily.

The complaint cited breaches of human rights including the right to freedom of speech, the newspaper cited the letter as saying, arguing that "even Samutsevich's suspended sentence for expressing her opinion is illegal".

Samutsevich also complained over breaches of the third article of the European Convention on Human Rights on torture or "inhuman or degrading treatment" during the women's trial, Khrunova said.

"I attached the timetable of the court hearings to the complaint," Khrunova told Moscow Echo radio station.

"You could see that all the days of the hearings ended after 9 pm. That meant they arrived back in their cells at midnight. And they had to get up again at 5am or 6am to go to the court again and prepare."

"That means they slept little throughout the day, did not eat at all, did not drink."

"From the point of view of the European Convention that is unacceptable treatment of people who are incarcerated."

Samutsevich and her bandmates Maria Alyokhina and Nadezhda Tolokonnikova were convicted of hooliganism motivated by religious hatred after performing a song critical of President Vladimir Putin in Moscow's main cathedral.

Samutsevich was released this month on appeal with a suspended sentence because she took a lesser part in the church performance where she was almost immediately grabbed by guards.