The trial will resume in Cape Town tomorrow after Dewani, 34, was extradited last month following a two-year legal battle that the Bristol-based businessman fought, claiming he would not get a fair trial in South Africa.
Three South Africans who were found guilty of the murder have accused Dewani as the planner of his 28-year-old wife Anni's murder.
Leopold Leisser is expected to testify that Dewani had paid him over thousand pounds on three occasions to have sex, the weekly Sunday Times reported today.
Anni's father Vinod Hindocha confirmed to the weekly that Leisser would be their key witness.
In Dewani's extradition hearings in the UK, there were claims that a witness, believed to be Leisser, had been told by Dewani that he needed to find a way out of getting married and that he would be disowned by his family if he tried to break off the engagement with Anni.
Also expected to testify is Anni's cousin and confidante Sneha Hindocha. Sneha is expected to testify about SMSs that Anni sent her complaining about Dewani's lack of intimacy towards her and also about how unhappy she was with him.
Another witness will be Zola Tongo, who is serving an 18-year sentence for Anni's murder after entering into a plea bargain with the state during which he said Dewani had approached him to find a killer.
Tongo then got Mziwamadoda Qwabe and Xolile Mngeni to carry out the contract killing.
After Dewani's first brief appearance in a South African court last month, he was remanded for psychiatric observation after his legal team submitted that he was suffering from severe depression and was therefore unfit to stand trial.
Tomorrow's court hearing is expected to be a brief pre-trial one which will include an update on Dewani's mental condition.
Sources close to the investigation said that there is likely to be a postponement to allow for further assessment of Dewani's condition.
Dewani has claimed that he and his wife were kidnapped at gunpoint while visiting the township of Gugulethu in November 2010.
Annie was found shot dead, but Dewani was not harmed.
