Heavily armed police are patrolling the capital of Papua New Guinea as a standoff continues between two men claiming to be prime minister.

Papua New Guinea's deposed Prime Minister Michael Somare was reinstated by a court this week but former Works Minister Peter O'Neill, 37, refuses to give up the reins of power, despite the Supreme Court ruling that he took power illegally.

O'Neill toppled Somare, 75, was while he was in Singapore having heart treatment earlier this year.

During Somare's absence, O'Neill was works minister under acting Prime Minister Sam Abal. But in August O'Neill joined opposition MPs to topple Abal. O'Neill was elected the acting prime minister in a parliamentary vote Aug. 2 and was sworn in that day the governor general.

O'Neill told a media briefing this week that he had ordered police to seize government buildings occupied by Somare. But so far police have taken no action and the situation remains calm.

Occupied buildings include the Prime Minister's Department, Government House and the Finance Department.

O'Neill said that because ''there are elements in Port Moresby police who have sided with Somare we've had to bring in additional policing personnel from outside Port Moresby to restore possession of government assets so the public service can continue to function. Anyone who has broken the law will face the full brunt of the law."

The political standoff is couched in constitutional language. O'Neill supporters, including most members of the 109-seat Parliament, claim Somare is no longer a member of Parliament because he has missed too many sessions due to his hospital treatment abroad.

Religious leaders, civil society groups and non-government organizations met at the Transparency International office to send a unified message that peaceful negotiations must resolve the standoff, a report by the Australian Associated Press said.

One solution could be a unity government, a "grand coalition," said Port Moresby's Catholic Archbishop John Ribat.

"If they are to release the tension they must come together and either form a grand coalition or negotiate a solution," a report by the Australian Broadcasting Corp. said. "The Melanesian way is to sit down and work out your differences. If this situation is prolonged I believe we will not avoid (violence). There are some opportunists out there that want to capitalize on the situation."

Bursts of gunfire have been heard around several government buildings but no injuries have been reported, AAP said.

Barry Holloway, a former speaker of PNG's Parliament, told The Age newspaper in Australia the Supreme Court was constitutionally correct in invalidating the election of O'Neill as prime minister in August. But "while it points the country in the right direction, it does not give a way forward," he said.

PNG, with a population of around 7 million, occupies the eastern half of the island of New Guinea and numerous offshore islands, off Australia's northern coast.

PNG is part of the British Commonwealth and as such has its official head of state Queen Elizabeth of the United Kingdom. But the government is elected by the population and officially recognized as ruling the country by the queen's representative, the governor general.

Papua New Guinea gained independence from Australia in 1975 after being administered by it since World War I.

PNG retains close links, both economic and military, with Australia, whose Foreign Minister Kevin Rudd has called for calm.