A London court had resumed hearings in the case after a reported improvement in the mental state of Dewani, who is wanted in South Africa there to stand trial.
However, Dewani's lawyer, Clare Montgomery, told Westminister Magistrates' Court at an initial hearing here today that he had suffered a relapse since then.
"We may have taken one step back having taken two steps forward," she said.
But a court spokesperson has confirmed that a full hearing will take place from July 1 and the case is scheduled for five days.
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The prosecution had informed the court last month that his mental state had improved and extradition proceedings, halted by the High Court on health grounds back in 2011, can be resumed.
The hearing in July is expected to be divided between two sessions - one to consider Dewani's health and the other to evaluate conditions inside custodial units in South Africa where he is likely to be held if extradited to the country.
He was later arrested by British police.
The care home owner from Westbury-on-Trym, a suburb of Bristol, denies any involvement in his wife's murder and has always maintained he wants to go back to clear his name.
In September 2011, British Home Secretary Theresa May had approved an extradition order for him to face trial in South Africa before it was halted by the High Court in London on mental health grounds.
Mziwamadoda Qwabe, referred to as the "Honeymoon Killer", had pleaded guilty to Anni Dewani's murder and was sentenced to 25 years in jail in Cape Town last August.
Co-conspirator Mziwamadoda Qwabe was sentenced to 25 years in prison after pleading guilty to shooting Anni Dewani.