At the start of this week, Papua New Guinea's often-volatile political landscape seemed relatively calm.

Prime minister Peter O'Neill's coalition controlled around 100 votes in the 111-seat parliament and he was still riding high on the excitement of the first lucrative shipments of liquid natural gas to Asia.

Fast-forward a week and PNG's political scene is in turmoil, with the prime minister's attempts to dodge corruption allegations sinking him deeper into a legal and political quagmire.

While the streets are calm, the leadership of the police force remains uncertain and many Papua New Guineans are finding voice online to vent their disgust at allegations of the same old crooked deals that have long held PNG back.

The trigger for the dramatic events that unfolded this week was the arrest warrant for official corruption served on Mr O'Neill on Monday, while he was at the offices of the company he once headed, Remington Group.

It might seem unusual to issue an arrest warrant rather than simply invite the leader in for questioning, but under PNG's criminal code the charge of official corruption requires an arrest warrant. It is also standard police practice in a place where absconding is the norm.

PNG's 'Games of Thrones' Take a look at the main players in the growing political turmoil in Papua New Guinea. Read more Read more

The warrant was signed by the chief magistrate and served by police, along with a letter from then-police commissioner Tom Kulunga, requesting Mr O'Neill show up at the fraud office at either 11:00am or 1:00pm that day.

The charges relate to payments of $28 million to Paraka Lawyers for work done for the Government between 2003 and 2006. This was well before Mr O'Neill took power in 2011, but the government still had not paid the bills and payment was finally authorised in 2012.

Just who authorised the payments is a crucial, disputed point.

A copy of a January 2012 letter apparently bearing Mr O'Neill's signature has emerged, instructing the Finance Ministry to make the payment. Mr O'Neill says it is a forgery.

But the country's main anti-corruption investigator Taskforce Sweep had ordered an independent analysis of the signature and a Sydney-based company Forensic Document Services confirmed it was that of Mr O'Neill.

The other piece of "fresh evidence" was a subsequent letter, in which Mr O'Neill reportedly tried to explain the disputed authorisation letter – the same document he claims does not exist.

It is clear from Taskforce Sweep's explanation of the new evidence that recently-sacked treasurer Don Polye has played a hand, providing a sworn statement and documents to the investigators.

As journalists waited outside the police fraud office, both the 11:00am and 1:00pm deadlines passed with no sign of Mr O'Neill.

Legal wrangling averts PM's arrest

Across town at Port Moresby's bustling court complex, Mr O'Neill's legal team were frantically trying to find a judge and have the arrest warrant restrained.

They managed to freeze the arrest overnight and returned on Tuesday to argue a rather convoluted reason for staying the arrest.

Instead of debating the legality of the arrest warrant directly, the PM's chief lawyer - the formidable Tiffany Twivey Nongorr - successfully had Mr O'Neill joined to a separate case that is deciding on the validity of the legal bills to Paraka Lawyers.

Ms Nongorr argued that it was improper to pursue Mr O'Neill for allegedly authorising the payment of bills that are still technically considered valid.

While the judge agreed to add Mr O'Neill as a plaintiff, he said it was up to lawyers to convince him why a civil court should intervene in a criminal matter.

When the court reconvened on Wednesday, there was a brief melee outside involving members of the public angry there was no more room in the packed courtroom and an unexpected tussle inside.

A new lawyer arrived late, still adjusting his legal robes, claiming to represent the police department on behalf of the newly-appointed acting commissioner, Geoffrey Vaki.

The battle for the bench reflected a wider struggle for control of the police force.

A hastily organised cabinet meeting removed previous police commissioner Mr Kulunga after his involvement in the arrest warrant.

Earlier, Mr Kulunga was convicted of contempt for not following a court order to reinstate Mr Vaki to a deputy position. Mr Vaki had been accused of pushing a woman out of a moving car, causing serious injury, but was cleared.

The lawyer representing Mr Vaki won the battle to speak for the police. He immediately took up the exact opposite position to the previous counsel and asked that the court grant a stay restraining police from arresting the prime minister.

The case was adjourned until June 25.

O'Neill sweeps away corruption taskforce

While Mr O'Neill's lawyers were fighting against the arrest, he was disbanding the body behind it, Taskforce Sweep.

The taskforce is a beast of Mr O'Neill's own making and has proved to be a fearless and effective investigator under the leadership of Sam Koim.

It had secured the rare conviction of a big fish, former national planning minister Paul Tiensten, who is serving a nine-year jail term. It also had numerous cases underway.

The prime minister claimed Taskforce Sweep had become compromised by political influence, possibly a reference to the involvement of disgruntled former-treasurer, Mr Polye.

Mr O'Neill's insistence that fraud investigators must be independent and that he would personally be in charge of cleaning out the system, was logic that baffled many. Likewise, the PM's claim that the sacking of key posts was needed to promote stability.

The prime minister said any ongoing corruption cases will be handed over to police and to the yet-to-be-fully-established Independent Commission Against Corruption.

He also announced a Commission of Inquiry into the Paraka affair, to be led by Australian Justice Warwick Andrew – a move widely seen as diversionary, but with intriguing implications if it went ahead.

In a memorable line, Mr Koim suggested Taskforce Sweep was shut down for unsettling powerful players.

"When you get close to the sun, you get melted," he said.

Police leadership under a cloud amid fresh political arrest threat

Throughout the week there remained genuine questions amongst the rank and file about who was in charge of the Royal Papua New Guinea Constabulary.

When the question was put to a constable at the front desk of a police station, he grinned slightly and said: "I'm not really sure."

The prime minister appeared to resolve the question when he appointed Mr Vaki, but doubt lingered. There was talk regional police bosses were lining up alongside sacked deputy police commissioner Simon Kauba.

But as the media set up cameras for a press conference on Wednesday, it was Mr Vaki who walked into the room. He was flanked by two senior officers but certainly not the reassuring entourage required at that moment.

Mr Vaki asked journalists not to read anything into the absence of top brass by his side, saying there was a training course on across town. It was less than convincing.

He also explained that he was in civilian attire because – after five years away from active duty – his uniform did not have the correct insignia and was with the quartermaster for an upgrade.

Mr Vaki's claims of pre-eminence were further undermined by the fact his own men had arrested him the previous day on charges of abuse of office and perverting the course of justice.

It is understood this relates to Mr Vaki instructing the new police lawyer to consent to the stay order in the case joined by Mr O'Neill, effectively stopping the police doing their job.

The regional police commanders who flew into Port Moresby during the week have not appeared publicly but are believed to be siding with Mr Kauba, in a faction determined to go after the PM's arrest.

Mr O'Neill has labelled this faction "rogue police officer" but they have not been deterred.

"We believe that all the actions of the PM since the service of the arrest warrant on him are designed to pervert the course of justice," Assistant Police Commissioner Thomas Eluh said in a statement on Friday.

Mr Eluh, who has emerged as a major player, said government cabinet ministers conspired with the prime minister and that police were considering charging them with various offenses.

While the police leadership and role in all of this remains uncertain, Brigadier General Gilbert Toropo has declared the military will back the government of the day.

On Saturday, Mr Eluh again called on the prime minister to answer police questions.

Former minister calls for O'Neill to resign

As the week drew to a close, rumours swirled that police had arrested the newly-appointed attorney-general, Ano Pala. They appear to be unfounded but that is clearly the ambition of at least a faction of the police.

The recently-sacked attorney-general Mr Kua, meanwhile, was most certainly free. On Friday afternoon, Mr Kua gave a press conference in which the measured delivery of a seasoned lawyer belied a searing attack against the prime minister.

PNG's political leadership - and sacked attorney-general Kerenga Kua (far right) - pose for a photograph. ( Supplied )

Mr Kua called on Mr O'Neill to resign, saying the prime minister had lost the trust of the public. He also outlined a larger issue involving proposed amendments to the constitution that he said could destroy democracy and threaten the very survival of the nation.

The proposed amendments are the latest moves to make votes of no confidence more difficult and avoid the political volatility PNG has faced in the past. Mr O'Neill successfully extended the grace period during which no-confidence votes are forbidden to 30 months.

But the latest proposed changes to Article 145 of the constitution would mandate that the replacement for any prime minister ousted by a no-confidence vote must come from the party that gained the most votes at the last election.

Mr Kua says this would remove the main motivation for opposition parties – the hope of one day taking control - thereby undermining PNG's Westminster system and pushing the country towards an "autocratic, dictatorial form of government".

Bizarrely, Mr Kua went straight from his eloquent take-down of the prime minister to the swearing-in of his party-mate Malakai Tabar as the new transport minister and was photographed smiling for the camera in a group shot with Mr O'Neill.

Political future unclear as legal battle, constitutional reform loom

In the so-called "land of the unexpected" it is foolhardy to predict how things will play out, however there are a few key things to watch closely next week.

On June 24, parliament will sit and is expected to consider the controversial constitutional amendment to Article 145.

Even if MPs pass the first reading of the bill, there must be a two-month wait until the second and third reading can pass it into law.

There is talk amongst anti-corruption activists of a protest on Tuesday, but it is yet to be seen how the colourful opinions on Facebook and Twitter translate to boots on the ground.

The following day, the prime minister's lawyers will return to court to take up the fight against the arrest warrant. Justice Ere Kariko made it clear that the burden was on Ms Nongorr to convince him why he should stop police arresting the prime minister.

Meanwhile, Mr Eluh says police are looking for attorney-general, Ano Pala, and will arrest him. Mr Eluh says police are also considering charges against the PM's legal team for its role in protecting the prime minister.

Grand chief Sir Michael Somare – who Mr O'Neill ousted in 2011 - has called on the prime minister to step down and answer the corruption charges.

But the nation's other elder statesmen – Sir Julius Chan, Paias Wingti, Dr John Momis – have not revealed their positions.

Canberra has kept quiet on the leadership tussle and the dismantling of PNG's only credible anti-corruption body, no doubt waiting to see who emerges victorious.

Mr O'Neill is a keen supporter of Australia's immigration policy and the $420 million development package that comes with the Manus Island asylum seeker detention centre.

But, aside from Australia protecting its own policy interests, political stability on our northern doorstep is a concern in its own right.