Members of an all-girl punk band who performed an anti-Vladimir Putin song in the main Moscow cathedral complained Wednesday they were too hungry and exhausted to participate in the high-profile trial.

On the eve of March's presidential polls, Nadezhda Tolokonnikova, Yekaterina Samutsevich and Maria Alyokhina barged into the Church of Christ the Saviour and performed a "punk prayer" against Putin who was running for a third Kremlin term.

They were arrested in March and now face up to seven years in a prison colony if found guilty of hooliganism.

"We are in a semi-conscious state. We are practically not getting any sleep. Today we did not sleep at all," Tolokonnikova, 22, said in court on the third day of full hearings.

She asked to submit a formal request to hold the trial in a way that would allow for meals and sleep. "We can sit here but we cannot fully participate," Tolokonnikova complained as the judge promised to call in medics for a second time in the day to examine the women.

Defence lawyers have repeatedly complained to the judge that the women are being woken up at 5:00 am at their detention centre to attend the closely watched hearings and are not fed for periods of more than 12 hours.

"We refuse to participate in an illegitimate trial. We ask the bailiffs to escort us out," said Alyokhina, 24, after the judge refused to accept their petition.

"Doctors have examined you. You are violating the court procedure," judge Marina Syrova said in a confrontational hearing, leading one of the defence lawyers, Violetta Volkova, to storm out complaining of high blood pressure.

The judge then issued Volkova a formal warning for leaving without permission, and continued to hear a witness ignoring the women's request to leave.

As the court went to a break, the judge said that medics had been called on the women's request and three ambulances arrived, an AFP correspondent reported from the scene. Defence lawyer Nikolai Polozov told journalists that all the women would be examined again.

Medics were called in earlier because Alyokhina collapsed over what a defence lawyer said was a reaction caused by her vegan diet.

"Maria Alyokhina suffered a severe drop in blood sugar levels this morning. This is linked to the fact that she is a vegan," and her diet in prison caused problems, Polozov said. She received injections from doctors, he said.

Volkova said the doctors had "merely raised her blood sugar levels, when in fact what she needs is an adequate meal and enough sleep."

Court officials said the women had been examined and ruled fit for trial.

As the women were led into the courtroom in handcuffs Tuesday, Alyokhina looked pale but told journalists that she felt "all right", with her forearm still bandaged after being given injections.

She had complained on Monday that "my head is spinning," as the hearing went on to almost 10 pm.

She said that each morning before being taken to the court the women were held for several hours in tiny airless square-metre cells known as "drinking glasses."

Their performance has been highly polarising in the predominantly Orthodox country.

The women testified Monday that their performance was a protest directed against Putin but conceded they could have made an "ethical" mistake by offending worshippers.

The prosecution has argued that their performance was aimed at insulting Orthodox Christians and was motivated by hatred.

The controversial trial has won Pussy Riot supporters among Western stars including pop icon Sting and British writer Stephen Fry and was condemned on Tuesday by the US State Department as "politically motivated."

The women were charged with hooliganism motivated by religious hatred of Orthodox believers in a case highlighting the Church's growing dominance under Putin.

"It's hard to find a rational explanation for why the absurd trial of Pussy Riot is continuing," said liberal daily Vedomosti.