Tens of thousands of Australians were among an all-time high number of people internally displaced in their countries due to natural disasters and conflict in 2019, newly released data has shown.

Key points: An estimated 18,000 Australians remain displaced after the catastrophic 2019/20 bushfire season

An estimated 18,000 Australians remain displaced after the catastrophic 2019/20 bushfire season Most internally displaced persons live in poorer countries, incapable of providing adequate medical care

Most internally displaced persons live in poorer countries, incapable of providing adequate medical care The United Nations and other organisations have urged ceasefires in light of the pandemic

The world reached a record 50.8 million internally displaced people last year, according a report by the Geneva-based Internal Displacement Monitoring Centre (IDMC), which warned of the additional threat posed by the COVID-19 pandemic.

About 33.4 million new displacements were recorded globally in 2019, the highest annual figure since 2012.

The IDMC reported 25,000 new displacements in Australia between January 1 and December 31, 2019 due to disasters — more than double the number reported in 2018.

A spokesperson for IDMC told the ABC a majority of these were displaced by the severe bushfire season which ravaged much of the country from mid-2019 until March this year.

Evacuees gather at McKenzies Beach, south of Batemans Bay. ( Supplied: Mark Cuddy )

"At least 18,000 people are expected to still be displaced from the unusually long and intense season," they said.

More than 10 million hectares burnt across Australia and 3,000 homes and 7,000 outbuildings were destroyed during the 2019/20 bushfire season.

Disasters were the largest source of displacement worldwide, causing almost 25 million people to flee their homes during 2019, the IDMC report said.

"The overwhelming majority of disaster displacement is climate-related, like 88 per cent," Justin Ginnetti, head of data and analysis at IDMC, told the ABC.

"Climate change is definitely going to have some impact."

Projections based on climate modelling from the Intergovernmental Panel on Climate Change show a fivefold increase in people displaced by floods globally by the end of the century, Mr Ginetti said.

"It's increasing in Asia, in South and South-East Asia, as well as in Sub-Saharan Africa."

The IDMC has not yet projected displacement numbers for disasters such as cyclones and bushfires, but Mr Ginnetti said global warming would likely result in a significant increase in those displaced by these disasters, too.

More than 4 million people were displaced in India, the Philippines, Bangladesh and China due to disasters, respectively, during 2019, while 916,000 were displaced in the United States.

Huge numbers were also displaced from their homes due to conflict and violence.

More than 1.8 million Syrians were displaced due to civil war in 2019, while 1.6 million people were displaced in the Democratic Republic of Congo.

A majority of internally displaced people around the world are in low- and middle-income countries, making them especially susceptible to the threat posed by the COVID-19 pandemic, IDMC said.

"IDPs are often highly vulnerable people living in crowded camps, emergency shelters and informal settlements with little or no access to health care," IDMC director Alexandra Bilak said.

"The global coronavirus pandemic will make them more vulnerable still."

"It will compromise their already-precarious living conditions, by further limiting their access to essential services and humanitarian aid," she said.

The rapid spread of the coronavirus has raised fears about the world's refugees and internally displaced people, many of whom live in poor or war-ravaged countries. ( IHH via AP )

"Year after year, conflict and violence uproot millions of people from their homes. Collectively, we are failing by epic proportions to protect the world's most vulnerable," Jan Egeland, secretary-general of the Norwegian Refugee Council, said in a statement.

"Politicians, generals and diplomats must rise above stalemates and seek ceasefires and peace talks, not guns and grenades. In this age of coronavirus, continued political violence is utterly senseless."

In March, UN secretary-general Antonio Guterres called for a worldwide ceasefire to focus on the "true fight of our lives".

"The fury of the virus illustrates the folly of war," he said.

Fragile ceasefires have since been called in some of the world's conflict zones such as Yemen, Myanmar and Ukraine, due to the pandemic.