The Foreign Affairs Minister says the re-appointment of Commodore Frank Bainimarama as Fiji's interim prime minister is a sham.
Nine ministers from the previous interim government, which was ruled illegal by the Court of Appeal on Thursday, have also been given back the same roles.
Foreign Affairs Minister Murray McCully says that the move takes Fiji down an even darker path and that the extent to which the commodore seems prepared to go to entrench himself and the military in power is unsettling.
Radio New Zealand's correspondent in Suva, Matelita Ragogo, says President Ratu Josefa Iloilo appointed Commodore Bainimarama caretaker prime minister at a swearing-in ceremony in Suva on Saturday morning.
Commodore Bainimarama, who overthrew the elected government in December 2006, was the interim prime minister from early 2007 till two days ago, when the Court of Appeal ruled that his government was unlawful, saying that on the basis of the 1997 constitution the President lacked the powers to validate the regime.
On Friday, however, Mr Iloilo revoked the constitution, sacked the judiciary, announced a new legal order and promised democratic elections by 2014 at the latest.
Not my decision, says Bainimarama
Commodore Bainimarama told Radio Australia that he had not influenced Mr Iloilo's decision to throw out the 1997 constitution, saying: "I explained to him the result of the court case, the appeal, and I guess he came up with that on his own."
The country has been placed under a 30-day state of emergency and the people have been warned that dissent will not be tolerated.
All media organisations are being monitored by the Ministry of Information, which has staff in newrooms to ensure that the public emergency regulations are observed.
UN Secretary-General Ban Ki-moon has deplored the latest developments and called for the urgent restoration of a legitimate government and constitutional order.