The trial of extradited British millionaire businessman Shrien Dewani on charges of ordering his wife's murder has been postponed until next month.

Mr Dewani appeared briefly in a Cape Town court, with his lawyers successfully arguing he was not yet fit to stand trial.

Lawyers for Mr Dewani, 34, said he was still unable to give lengthy testimony.

A judge ordered him to appear in court again on 20 June and he was remanded in custody at a psychiatric hospital.

Mr Dewani denies ordering the killing of his 28-year-old bride Anni in Cape Town in November 2010.

He claims the couple were kidnapped at gunpoint during their honeymoon as they drove through the Gugulethu township in a taxi.

Mr Dewani escaped unharmed, but his wife's body was found in the abandoned car the next day. She had been shot dead.

Prosecutors allege Mr Dewani hired South African Xolile Mngeni to kill his wife.

Mr Mngeni was jailed for life for the murder in December 2012.

Two other men also jailed over the killing allege that Mr Dewani ordered the murder.