A killer, a sexist, a corruption fighter, and a saviour.

Key points: Filipinos at home and abroad will vote in mid-term elections by May 13

Filipinos at home and abroad will vote in mid-term elections by May 13 Despite allegations of human rights abuses, Mr Duterte enjoys great popularity

Despite allegations of human rights abuses, Mr Duterte enjoys great popularity Experts have speculated this is due to the Philippines' idiosyncratic political culture

Philippines President Rodrigo Duterte has been labelled a number of things since his election in 2016, but conventional is not one of them.

Mr Duterte currently rules over a vast archipelago of 7,000 islands, which are home to a fiercely Roman Catholic population and an equally fervent Islamic minority in the country's south.

On Monday, about 60 million Filipinos will vote in congressional mid-term elections that may embolden or weaken Mr Duterte's six-year term, which is due to expire in 2022.

The mid-terms, modelled on the US congressional mid-terms, will largely be seen as a referendum on the idiosyncratic presidency that Mr Duterte has forged; current polls show his administration on its way to wiping out the Opposition.

Early voting opened on April 13 for more than 1.8 million Filipinos who are overseas and are able to vote in consulates or by post.

Filipinos made up Australia's fifth-largest migrant group in 2018, according to the Australian Bureau of Statistics, and there are more than 9,000 Filipinos in Australia who are eligible to vote.

There is a range of views on Mr Duterte's presidency, and some do not match up with the global chorus of disdain he has attracted since his election.

"We may think from his language, from the way he acts, that he is a country bumpkin, but actually he reads a lot, and he knows a lot," said Filipino-born Reynaldo Ileto, an honorary professor in Asian history and postcolonial studies at the Australian National University.

"I'm not an apologist for Duterte, but I very much understand what makes him tick.

"Most of my colleagues [in academic circles] are anti-Duterte, and they do not understand why I won't join them … above all, I'm trying to understand why he still gets [near] 80 per cent popularity ratings."

'The most important thing is now, not the future'

The Duterte administration has been accused of being complicit in a raft of extra-judicial killings. ( Supplied: Vincent Go )

Overseas, the Duterte Administration has received largely negative attention, with the President being accused of indirectly overseeing a wave of indiscriminate extra-judicial killings by Filipino police and unmarked vigilantes as part of an anti-drug agenda that swept him to power in 2016.

Mr Duterte first trialled his "strongman" style and "tough on drugs" approach when he served as vice-mayor and mayor of Davao City in Mindanao — a poorer municipality in the country's south that is also home to armed separatist insurgencies — for nearly 30 years.

Investigations have revealed the victims of his campaign range from poor adolescents to high-level drug dealers, but presently there remains only anecdotal evidence that Mr Duterte has been directly responsible for the killings.

Filipino-born ANU PhD candidate and mid-term researcher Cleve Arguelles told the ABC that a lot of President Duterte's domestic popularity hinges on his ability to deliver immediate solutions to the country's ills — regardless of the means.

"Duterte's enduring popularity among his supporters — even for those who come from communities victimised by the president's war on drugs — is his capacity to make visible, give voice, and effectively respond to the conditions of everyday misery long experienced by them," he said.

"Many of Duterte's supporters also argue against critics who do not understand the value of immediate, albeit temporary relief caused by the drug war to their communities.

"The important thing is now, not the future, since most of them, as they say, will all be dead in the long-run."

Human rights observers say extra-judicial killings overwhelmingly target the poor. ( Supplied: Vincent Go )

In November 2018, the Philippines Drug Enforcement Agency (PDEA) said police had killed 5,050 people since the launch of the administration's anti-drug operations, and arrested more than 164,000.

The Government's official numbers have been disputed by a number of different organisations. In 2018, Human Rights Watch estimated the number of killings to be closer to 12,000, citing a further tally from unidentified vigilantes.

"Think of the emerging middle class — with properties they've worked hard for — who are threatened by the absence of reasonable security in their communities," Mr Arguelles said.

"Poor communities also blame the rogue cops, not the President, for the excesses on the war on drugs."

And as the body count has risen, Mr Duterte has ratcheted up his rhetoric against drugs, telling a State of the Union address in 2018 "[the] illegal drug war will not be sidelined".

"Instead it will be as relentless and chilling, if you will, as on the day it began," he said.

For those looking on from abroad, Mr Duterte's apparent lack of impunity is a cause for concern.

And the President's unpolished behaviour has also raised brows around the globe.

In 2016 he infamously called former US president Barack Obama a "son of a bitch", while in 2018, he told Filipino soldiers to shoot female insurgent soldiers "in the vagina", adding that without them "[women] would be useless".

'Gods, guns and goods': Duterte set to swamp competition

Mr Duterte is regularly greeted by large crowds across the country. ( Supplied: Philippines Presidential Office )

Yet despite the negative attention Mr Duterte receives, he continues to enjoy incredible support from eligible voters both in the Philippines and around the world.

In April, non-profit polling organisation Social Weather Station found 79 per cent of Filipinos were satisfied with the President's performance, a new personal record.

Mr Arguelles maintains that in contrast to traditionally slow democratic processes, part of Mr Duterte's popularity is found in his vicious opposition to incremental yet precarious progress.

"[Filipinos] cannot wait for long, messy and unpredictable processes of letting the courts decide, or having the drug addicts undergo rehabilitation, only for the temporary relief they are enjoying to disappear again," he said.

And for the observers who still scratch their heads at Mr Duterte's seemingly insurmountable popularity, Dr Ileto suggested history may be able to partially explain it.

During the American conquest between 1898 and 1902, the "real opposition" came from the local mayors — the highest political position available to Filipinos over the 300 years of Spanish rule, he said.

"So when Duterte [being a former mayor] came out [as a candidate], as being a strong nationalist and critical of American intervention — this was familiar," Professor Ileto said.

As President, Mr Duterte has stuck to his guns, striking a discordant tone with Manila's traditional ally (and former colonial rulers) in Washington, and instead pursuing closer relations with China.

"Duterte has not even been to Washington," Professor Ileto said.

For any close political observer, such as Nicole Curato, a senior research fellow at the Centre for Deliberative Democracy and Global Governance at the University of Canberra, the musical chair-like cycle of dynastic politics is central to Filipino democracy.

"By design, elections in the Philippines are viewed as a mechanism to moderate inter-elite competition," she said.

The President's daughter, Sara Duterte, is the current mayor of Davao City, and is leading a Senate campaign made up of 13 candidates, including Imee Marcos, the daughter of the Philippines' former dictator Ferdinand Marcos.

Late dictator Ferdinand Marcos remained unburied from his death in 1989 until 2016. ( Reuters: Erik De Castro )

In time, either daughter could eventually take the presidency if the right circumstances prevail.

Mr Duterte enjoys support from both the Marcos family and the former president Gloria Arroyo, who is the outgoing speaker of the House of Representatives.

Both surnames draw significant support in their home electorates, and according to Ms Kotsakis, the country's "semi-feudal" characteristics make electorates ripe for manipulation.

Sara Duterte is the heir apparent to the Duterte dynastic throne. ( National Historical Commission of the Philippines )

"Voters tend to see a lot of improvement in their own electorates such as [Imee Marcos's] Illocos Norte, and sometimes people are given token gifts in the lead-up to the election," she said.

"Because people feel indebted, that's why the dynasties reign."

Meanwhile, most people maintain Mr Duterte's administration is set for victory come Monday, an outcome aided by the Opposition's sheer lack of resources and the public's wish to reward its straight-shooting head of state.