Menzi Simelane, national head of the prosecution service, appeared to have pre-judged the honeymoon murder-accused in a television interview in February.
During the interview on South African television, he told SABC3: "This is a pure criminal matter of somebody who murdered his wife whilst he should be celebrating his honeymoon. The facts here are that the accused that is sought to be extradited came to the country and committed what is a very heinous crime."
The comments prompted Mr Dewani's publicist Max Clifford to say it was "absolutely frightening" that Menzi Simelane appeared to have pre-judged the case.
The development followed criticism of South Africa's national police commissioner Bheki Cele, who described Dewani as a "monkey". He has since been suspended amid allegations of corruption.
Dewani is currently appealing against an order that he can be extradited to South Africa over the alleged contract murder of his new wife, Anni, 28, on their honeymoon in Cape Town last November. The High Court challenge will take place in London on December 13 and 14.
The South African Supreme Court ruled Menzi Simelane is to be removed from office, saying the decision of president Jacob Zuma to appoint him was invalid and "inconsistent with the constitution".
The judgment followed a case brought by South African political party the Democratic Alliance, which claimed Simelane was not a "fit and proper person" to hold the position.
Dewani family lawyer Charlotte Harris said: "The South African police have refused to interview Shrien Dewani regarding any allegations, preferring instead to extradite him. Mr Dewani remains committed to clearing his name when he is fit and well enough to do so and when his personal safety can be guaranteed."
Mrs Dewani, 28, from Sweden, was shot when a taxi the couple were travelling in was hijacked in the Gugulethu township on the outskirts of Cape Town on November 13. Taxi driver Zola Tongo, who has admitted his part in the crime, claimed in a plea agreement with prosecutors that Dewani ordered the carjacking and paid for a hit on his wife.
