Frank Bainimarama has pledged fresh elections but is yet to set a date
A court in Fiji has ruled the military government was illegally appointed after a 2006 coup, and that democracy should be returned as soon as possible.
The Fiji Court of Appeal - the nation's second highest court - said an interim prime minister should be appointed to dissolve parliament and call elections.
Military ruler Frank Bainimarama is expected to address the nation later.
His military regime toppled the civilian government in December 2006, in Fiji's fourth coup in 20 years.
Commodore Bainimarama faces a 1 May deadline to set a date for elections or face suspension from the Pacific Islands Forum, a regional trade and diplomatic bloc.
In March the Commonwealth gave Fiji a six-month deadline to restore democracy or face full suspension of its membership.
'A fresh start'
Delivering the verdict, Judge Randall Powell said: "In our opinion, the only appropriate course at this time is for elections to be held to enable Fiji to get a fresh start.
He said that the appointment of a disinterested caretaker prime minister "would enable Fiji to be restored to democratic rule in accordance with the Fiji constitution".
In reaction, the regime's attorney general said if the ruling was implemented, the country would be left with a dangerous "vacuum". He signalled that an appeal would be lodged.
The decision overturns last year's ruling by the Supreme Court that the military-led government was legal.
In 2008, the Supreme Court rejected a case by ousted prime minister Laisenia Qarase that questioned the legality of the 2006 military coup.
Mr Qarase said that Frank Bainimarama's actions were in breach of Fiji's constitution, and that all the decisions and appointments made since the coup had been unlawful.
The military regime argued it was not Mr Bainimarama who had authorised the takeover, but President Ratu Josefa Iloilo, who exercised his powers under the constitution to dismiss Mr Qarase's government in the face of a political crisis.