PORT MORESBY -- Papua New Guinea's reform-minded prime minister's chances of regaining power in the South Pacific's shambolic and violent election dimmed further on Friday after seven opposition parties agreed to form a coalition.

The leaders from the seven parties, including former prime ministers Sir Michael Somare, Julius Chan and Bill Skate, said their potentially election-winning coalition could grow to eight and give impoverished Papua New Guinea "a new lease on life".

"We know that we are getting closer towards formation of government," Somare, independent Papua New Guinea's founding father and head of a leading political dynasty, told reporters late on Thursday, Reuters reported.

"I think peoples have spoken and they have given us a clear indication. They want us to lead the government," said Somare, who is known through Papua New Guinea as "chief".

The chaotic ballot started on June 15 and should have ended on June 29 but had to be extended by more than two weeks because of violence and widespread voting irregularities.

around 25 people have been killed.

According to the latest results, the new opposition coalition has so far won around 32 seats in the 109-seat Parliament against just eight seats for prime minister Sir Mekere Morauta's People's Democratic Movement (PDM).

But only 70 constituencies have so far been declared and it remains unclear whether officials will be able to announce any results in the strife-torn highlands, where armed gangs intimidated voters, stole ballot boxes and barricaded towns.

--- Deepening Instability --- Rich in oil, gas, copper and timber but mired in corruption and lawlessness, Papua New Guinea has slipped into deepening instability since winning independence from neighboring Australia in 1975.

Most of its 5.1 million people eke out subsistence lifestyles in the jungle-clad highlands, where tribal warfare and crime are common and people cling to ancient beliefs like black magic.

Morauta, regarded by multilateral lenders as Papua New Guinea's best hope for economic revival, has become increasingly vitriolic about Somare, who quickly emerged as his chief rival in Papua New Guinea's seventh election since independence.

An advocate of decentralization, Somare became Papua New Guinea's first prime minister after independence and again from 1982-85. Both times his term ended with a vote of no confidence.

Earlier this week Somare launched a high court challenge against the extension of the election, arguing Parliament should be recalled even if balloting in the highlands was a shambles.

The government responded with its own application in the country's highest court for an even longer extension to allow the highland elections to be concluded.

Morauta said Somare's attempt to end the vote counting represented "a blatant grab for undemocratic power" because it would mean that up to 40 percent of Papua New Guineans were not represented in the next Parliament.

"The man who is tagged the father of the nation is prepared to trample on people's democratic rights in his desperation to become prime minister," Morauta said.

The Supreme Court is expected to rule on the issue next week. In the meantime, the agreement reached by the opposition parties would bind them for five years.

The coalition includes Somare's National Alliance, the People's Progress Party, People's Action Party, People's National Congress, the Melanesian Alliance, the PNG National Party and the United Resource Party.

Its leaders said it could be joined next week by the Pangu Pati if it resolves a leadership challenge this weekend.