Australia urged restraint on Thursday in Papua New Guinea after police arrested the country's chief justice and attempted to charge him with sedition.
The poverty-stricken but hugely resource-rich country has been stuck in a political impasse for months with the Supreme Court ruling again this week that Prime Minister Peter O'Neill's rise to power was illegal.
It said veteran leader Sir Michael Somare should be reinstated.
O'Neill claimed the judiciary was biased and rejected the decision, which led Thursday to Deputy Prime Minister Belden Namah and 10 police storming into the court to arrest Chief Justice Sir Salamo Injia.
ABC radio reported from the capital Port Moresby that after more than two hours of negotiations, police escorted Injia to a courtroom for a formal interview.
Assistant commissioner Thomas Eluh said he expected to charge him with sedition after Namah warned Injia and two other judges who handed down this week's ruling they should resign within 24 hours or be arrested.
Australian Prime Minister Julia Gillard spoke to O'Neill to express her concerns and urge restraint, the Australian Associated Press reported.
Foreign Minister Bob Carr said he also called his counterpart Ano Pala and gave the same message.
"Papua New Guinea has taken the crucial decision to proceed to elections in accordance with the constitution -- to give the PNG people the chance to determine their national leadership," Carr said.
"It is important that recent events not distract from proceeding to those elections in a peaceful and orderly way.
"Australia remains fully committed to assist Papua New Guinea in the planning and holding of its elections."
Somare, 76, is expected to be a key figure in national polls scheduled to begin on June 23.
The court ruling delivered Monday is the second to find that O'Neill's appointment as premier, which happened while Somare was recuperating from serious illness, was invalid.
Somare, who was PNG's first leader after independence, suffered ill health in 2011 and his family announced last June that he had resigned as leader while hospitalised in Singapore.
But he recovered and returned to challenge O'Neill, who had been elected by lawmakers to the top job in August, and won the support of judges who said he should be reinstated.
Impoverished PNG has been struggling to throw off its reputation as a politically dysfunctional and often lawless nation, and has a huge liquefied natural gas project, led by US-based corporation ExxonMobil, under way.© ANP/AFP