Indian women participate in a protest in Mumbai to condemn a deadly car crash that left a woman who accused a politician of rape in critical condition. Picture: Rajanish Kakade/AP

New Delhi - India's Supreme Court on Thursday moved the rape trial of a powerful regional politician to the capital, New Delhi, to allay fears he could influence the outcome, a further embarrassment for the Hindu nationalist ruling party.

Federal police opened a murder investigation this week against Kuldeep Singh Sengar, a legislator from northern Uttar Pradesh state, after a truck crashed into the car of the young woman who accuses him of rape. Two of her relatives were killed in the crash on Sunday and she is fighting for her life in hospital.

He denies the rape and any involvement in the car crash.

The case has led to anger at Prime Minister Narendra Modi's Bharatiya Janata Party (BJP), which also controls the regional government in Uttar Pradesh, India's most populous state. Opposition groups accused the party of protecting Sengar.

The party expelled Sengar on Thursday, a decision taken by its national leadership, led by Modi's close aide Amit Shah, BJP's Uttar Pradesh unit said in a statement late on Thursday.

The Supreme Court directed that the case be moved out of Uttar Pradesh, and that the investigation into the car crash should be completed within seven days.

Chief Justice Ranjan Gogoi set a 45-day deadline to resolve the rape case, which has made little progress in Uttar Pradesh. He ordered the Uttar Pradesh state government to pay the accuser interim compensation of 2.5 million rupees ($36,200).

Sengar's lawyer Awadhesh Singh told Reuters he would fight the case wherever it was being heard: "We were fighting here, and we will continue to fight there also."

Kuldeep Singh Sengar, a legislator of Uttar Pradesh state from India's ruling BJP, reacts as he leaves a court after he was arrested in connection with the rape of a teenager. File picture: Pawan Kumar/Reuters

The case was thrust into the spotlight last year when the accuser, who was a teenager in 2017 when she says she was raped, tried to kill herself, accusing the police of inaction.

People shout slogans as they carry an effigy depicting Kuldeep Singh Sengar, a legislator of the ruling BJP, during a protest demanding justice for a woman who is fighting a rape case against the legislator in Kolkata. Picture: Rupak De Chowdhuri/Reuters

The main opposition Congress party said the decision to move the case out of Uttar Pradesh points to a dire law-and-order situation under the state's chief minister, Yogi Adityanath, a monk-turned-politician who says crime has fallen on his watch.

"The Supreme Court's order is proof that Adityanath's government is neither able to maintain law and order, nor punish criminals," a Congress spokesman, Randeep Singh Surjewala, said on Twitter.