Ukraine's former prime minister Yulia Tymoshenko has returned to court after her arrest sparked global concern.

Judge Rodion Kireyev swiftly rejected a request by her legal team to reverse Friday's order to place her under arrest.

The opposition leader was delivered to court in central Kiev in a prison van hours before the trial was due to open as hundreds of supporters outside shouted ‘Yulia!’ and ‘Hands off Tymoshenko!’.

She yelled ‘Glory to Ukraine!’ as the judge entered the cramped courtroom and showed no sign of softening her attitude to the court.

‘I will not stand in front of you, because it would be kneeling in front of the mafia. You are not breaking me but Ukraine's young democracy,’ she told the judge.

The authorities have so far made no attempt to remove a camp of dozens of tents set up by her supporters outside the court. But units of the anti-riot police arrived in a half dozen buses in the early morning.

Despite spending the last three nights in prison after her arrest on Friday, Ms Tymoshenko was immaculately turned out with her trademark hair braid wrapped around her head.

‘Prison is prison but I am not going to complain,’ she told her supporters. ‘This is a test, but it is also the mission of my life, to help Ukraine become a true European state.’

The judge however said the defence had presented no convincing argument that her detention conditions needs to be changed and gave Ms Tymoshenko another warning for her ‘mafia’ comment.

She was accompanied by two priests. Her husband Olexander also appeared in court to provide support. Her former interior minister Yuriy Lutsenko, imprisoned and on trial, was taken to court in the same van.

Ms Tymoshenko, who is on trial on charges of abuse of power over gas deals she signed with Russia in 2009, was placed under arrest for contempt of court after describing her successor as ‘corrupt’ and mocking the judge on Twitter.

She says she is the victim of a vendetta pursued by current President Viktor Yanukovych against leaders of the 2004 Orange Revolution uprising that brought a pro-Western government to power.

EU members and the US expressed alarm after her arrest, saying they were concerned about a selective prosecution by the Yanukovych-led authorities of their foes.

Her lawyer Sergei Vlasenko has said he fears she risks being handed a jail sentence of between seven and ten years.

Mr Yanukovych's administration had denied having anything to do with the trial.