This week world leaders will descend on Papua New Guinea for the Asia Pacific Economic Cooperation (APEC) Summit, an event that has become controversial before it has even started.

Key points: 15,000 people to descend on one of the world's least liveable cities

15,000 people to descend on one of the world's least liveable cities Government blasted for buying 40 Maseratis for APEC delegates

Government blasted for buying 40 Maseratis for APEC delegates Australia and China splash cash and jockey for influence in the region

You might remember APEC from pictures of world leaders in colourful shirts, or even for the infamous prank by The Chasers War on Everything when Sydney hosted the annual event.

But the APEC summit is a big deal for the Asia Pacific region, and is an important opportunity for Australia to forge new foreign policy and strengthen bonds with our close neighbours and international trade giants like the United States and China.

To help you get a grasp of what APEC is all about and what's gone on behind the scenes, here is a breakdown of this year's conference by the numbers.

21 countries, 180 meetings but no Trump or Putin

All eyes will be on Port Moresby during the summit. ( Wikimedia Commons )

APEC is made up of 21 countries including Australia, together accounting for 2.7 billion people — more than a third of the world's population.

Who is going? It will be Scott Morrison's first APEC summit as Prime Minister

It will be first APEC summit as Prime Minister China's President Xi Jinping will be one of the key players at the event

China's President will be one of the key players at the event The leaders of Taiwan and Hong Kong will also be in Port Moresby

The leaders of and will also be in Port Moresby Canada's Justin Trudeau , South Korea's Moon Jae-in and New Zealand's Jacinda Ardern will also be there

Canada's , South Korea's and New Zealand's will also be there Donald Trump won't be making the trip , sending Vice-President Mike Pence on behalf of the US

, sending on behalf of the US Likewise, Vladimir Putin will be absent, sending Russian Prime Minister Dmitry Medvedev in his stead

Started in 1989 as part of a push by prime minister Bob Hawke to encourage a strong regional economy around the Pacific Rim, most of the APEC members are from our neighbouring region with the addition of Russia, United States, Canada, Mexico, Chile and Peru.

It is an important economic group for Australia, with more than 70 per cent of our trade conducted with other APEC countries, according to the Department of Foreign Affairs and Trade (DFAT).

Marked by dry economic discussion and high-profile side meetings, the annual leaders summit boasts a busy schedule — with 180 official meetings and heaps of other events over the course of the summit.

Leaders from around the world, including Prime Minister Scott Morrison, Chinese President Xi Jinping and New Zealand's Jacinda Ardern will be attending the summit.

While last year's summit in Vietnam was largely overshadowed by the sideline talks between US President Donald Trump and Russian President Vladimir Putin, both leaders will be absent this year.

15,000 to descend on one of the world's least liveable cities

Port Moresby is the world's fifth-least liveable city. ( ABC News: Jarrod Fankhauser )

PNG is the poorest nation of the entire APEC group.

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Fewer than 400,000 people usually live in the capital, which is the world's fifth-least liveable city, according to the Economist's Global Liveability Index 2018 — citing concerns over health care, infrastructure, and education.

But during the APEC leaders week, close to 15,000 delegates will be in Port Moresby, followed by the world's media and security teams.

To accommodate such an influx of visitors, three Australian cruise ships will station themselves in Port Moresby's harbour, which the PNG Government says will house approximately 4,000 of the delegates.

Some 4,000 members of the PNG disciplinary forces and their international counterparts will be patrolling the city for the summit.

The Government says hosting the summit will bring millions in investment after putting PNG on the map, and Prime Minister Peter O'Neill says he expects $85 million will be spent by leaders during the time of APEC alone.

In what police referred to as part of security procedures, the PNG Government last week sent at least 21 refugees that were in Port Moresby for medical treatment back to Manus Island.

The donning of local garments is a longstanding APEC tradition as shown by presidents Trump and Putin in 2017. ( Reuters: Sputnik/Mikhail Klimentyev/Kremlin )

40 Maseratis for visiting dignitaries

Questions were raised when 40 luxury Maseratis landed in Port Morseby. ( ABC News: Natalie Whiting )

To pay for the summit, PNG has allocated $330 million (or 800 million kina) to spend in over three years.

That does not include the $72 million spent on the construction of summit centrepiece APEC House, which the Government says is being built with tax credit.

But in 2016, the International Monetary Fund, which is one of the world's pre-eminent economic bodies, estimated hosting the summit would cost $1.5 billion over 3 years.

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Mr O'Neill had said the benefits to the nation would outweigh the amount spent by the Government.

It comes at a time of deep uncertainty for the PNG economy, with the 2018 budget saying the country's deficit would reach 2 billion kina, or around $800 million by 2019 — a number critics say is conservative, and could be much higher.

Some 37 per cent of PNG's population live below the poverty line, according to the United Nations Development Programme.

With a tight budget, questions were raised when 40 luxury Maseratis landed at Port Moresby's Jackson International airport, brought in for the leaders to use for the meetings.

The cars retail in Australia for between $209,000 and $345,000.

The Government said the cost will be recouped by selling them to the private sector after the event, and that they're appropriate for the status of the visiting dignitaries.

Three Bentley Spurs have also reportedly been acquired for the summit.

News of the cars prompted outrage over spending on APEC, with thousands reportedly staying home in a small, nationwide strike.

Many on social media pointed to the purchase of the cars as unnecessary, particularly with the news that a child had died from polio on the back of years of cuts to the health budget.

PNG had the virus under control until an outbreak was detected in June. ( Supplied: UNICEF/PNG/Kana )

Port Moresby's Jackson's International Airport has also received a cash injection, with a $30 million upgrade.

But it is understood there will not be enough room for all of the planes, so Australia has offered up Cairns airport to park planes there, which is some 844 kilometres away from the capital.

The ABC understands that US Vice-President Mike Pence will be one of those making use of the Australian offer, deciding not stay in Port Moresby and instead making the 1.5-hour commute from Cairns for the two days he's attending the summit.

China's $35m convention centre vs 1,500 ADF personnel

The International Convention Centre is a $35 million showpiece of Chinese engineering. ( ABC News: Eric Tlozek )

This year's APEC summit comes at a time when the Pacific has become a hotbed for concerns about China's growing campaign to increase their global influence.

PNG, which is the one nation signed up to China's One Belt One Road initiative, has been a key beneficiary of Chinese investment and many of it's infrastructure projects will be in display in Port Moresby.

Much of the summit will take place in a $35 million convention centre built with Chinese aid and Beijing has donated nine fire engines, along with 50 coaches and 35 mini buses for use at the event.

While Australia still remains PNG's biggest aid donor, Canberra is not providing any direct financial assistance for the APEC summit.

Instead, Australia's assistance comes in the form of security, with estimates the assistance will cover $130 million of the total APEC costs.

During the busiest period of the leaders' week, there will be 1,500 Australian Defence Force personnel supporting PNG's Joint Security Task Force, with just under 500 of those on the ground in Port Moresby.

To assist them, there will be up to 16 Super Hornet aircraft deployed to North Queensland and three Australian Navy ships are stationed off Port Moresby, accompanied by one helicopter landing dock and several patrol boats.