Professor Sean Davison will appear in the Dunedin district court again on a charge of attempted murder on November 16, but his passport has been confiscated and it is unclear whether he will be able to return to South Africa after the November court appearance.
He is the head of the forensic laboratory in the biotechnology department at the University of the Western Cape (UWC), and lives in Milnerton.
"We're currently going through a difficult time," his wife, Raine Davison, told Die Burger on Sunday.
"He went to a conference in Australia in September, and after that he went to his family in Christchurch because there had been an earthquake."
Davison was presumably arrested at his family's house, UWC spokesperson Luthando Tyhalibongo said on Sunday.
Davison wrote in a book last year how his mother, Doctor Patricia Ferguson, had asked him to help her die.
He went to New Zealand in 2006 to visit her, and she died in October that year at the age of 85. Ferguson was a retired general practitioner and psychiatrist. In 2004 she was diagnosed with terminal cancer.
She tried to hasten her own death by starving herself, the New Zealand Herald and Otago Daily Times reported.
In the original manuscript, Davison described how he had given her a lethal dose of morphine, but this was not published in the book Before we Say Goodbye.
However, the omitted section of the manuscript was leaked to the New Zealand Sunday Herald shortly after the book was published in June 2009.
"I did not intend for the details of my mother's death to end up in the public sphere, but I realised it might happen," he told the newspaper at the time.
"One of the reasons it was not included in the book was the possibility of legal action, which I think would be utter nonsense in this case."
According to reports in the New Zealand media, he appeared in the Dunedin district court on September 24 and again on September 27.
He was released on bail.
Tyhalibongo said Davison will retain his post, pending the outcome of the court case. He has been working at the university since 1995.
Davison's work involves, among other things, identifying bodies buried in mass graves during the apartheid years by means of DNA tests.