Australia and the Commonwealth have called for restraint in Papua New Guinea amid escalating tensions over the leadership battle.
On Friday a group of police were said to be blockading parliament, a day after PNG's chief justice was charged with sedition.
The chief justice had ruled that Sir Michael Somare was PNG's legitimate prime minister.
But Peter O'Neill also claims the post and is effectively running the country.
Parliament elected Mr O'Neill prime minister while Mr Somare was out of the country receiving medical treatment last year.
Earlier this week, the Supreme Court reaffirmed its earlier ruling backing Mr Somare as prime minister.
The chief justice was then arrested on Thursday, after a stand-off of several hours, and is now facing charges.
'Peaceful and orderly'
Mr O'Neill says the judiciary is biased towards Mr Somare and wants to reconvene parliament to discuss the court's ruling.
But a group of several dozen police outside parliament were reported to be blocking both entrances. It is not clear on whose orders the police are acting.
General elections are due to be held in the country in June.
In a statement issued late on Thursday, Australian Foreign Minister Bob Carr urged all sides "to act with restraint in very difficult circumstances".
"Papua New Guinea has taken the crucial decision to proceed to elections in accordance with the constitution," the statement said.
"It is important that recent events not distract from proceeding to those elections in a peaceful and orderly way.
The Commonwealth bloc has also called on PNG to respect the rule of law.
Commonwealth Secretary-General Kamalesh Sharma "urged all parties to exercise restraint in their actions and to ensure a peaceful and constructive resolution to the present situation through democratic and lawful processes".