SUVA - The military has finally seized control in Fiji in the fourth coup in 20 years after days of shadow boxing.

At a press conference at 7pm, Commodore Frank Bainimarama said he had established military law in Fiji and installed himself as President.

"As of six o'clock this evening, the military has taken over the government, has executive authority and the running of this country," Bainimarama told reporters.

He added: "We urge all citizens to stay calm."

New Zealand Prime Minister Helen Clark immediately branded the Commodore as "deluded" and said his actions were a "display of military arrogance".

And Fijian PM Laisenia Qarase said the action was illegal, a "national embarrassment" and the action "raped" the Fiji constitution.

The coup came after days of pressure by the military in an effort to force Qarase to step down.

A calm-looking Bainimarama read a lengthy statement which included legal arguments over the military's right to take control under what he called the "doctrine of necessity".

"Having taken over from the president I dismiss the Prime Minister Qarase."

He said soldiers would accompany police on patrols through Fiji and he gave Cabinet Ministers one month to clean out their desks in Government.

"The stalemate has forced me to step forward and the military has taken over government," Bainimarama said.

He said Prime Minister Laisenia Qarase's refusal to agree to President Ratu Josefa Iloilo's request to resign had left Fiji in "limbo" and forced him to act.

Bainimarama said the interim prime minister would be Jona Baravilala Senilagakali, a former Army medic in his 70s who has little political experience except as head of the Fiji Medical Association.

Asked how effective the new interim prime minister would be, given his lack of political experience, military spokesman Major Neumi Leweni said: "What do you mean he's got no qualifications. That's your interpretation".

Senilagakali was paraded before the media following the press conference but did not take any questions.

The coup, the fourth in 20 years, came after a prolonged period of uncertainty in which the military and the Government squared off over controversial laws.

At a press conference tonight, Qarase said a military regime was "illegal and unconstitutional".

He was quoted on fijilive.com as saying; "What the military commander has done is that he has raped the constitution and we have become the laughing stock of the world.