It's the biggest humanitarian crisis since WWII and Australians don't know about it.

It’s a humanitarian crisis on a scale of World War II – yet most Australians have no clue about it, and those that do know don’t seem to care.

A recent poll shows two-thirds of Australians have no idea 23 million people are starving poor nations of Yemen, South Sudan, Nigeria, Somalia and other East African countries.

Essential Media surveyed 1013 people about their knowledge of the famine in Africa and willingness to donate, on behalf of aid group Caritas Australia.

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Sadly, less than a quarter of those surveyed said they would donate if they knew about the crisis.

The staggering 65 per cent surveyed who said they would not donate, listed a range of reasons for not doing so, including a lack of money or preferring to support causes closer to Australia.

Caritas Australia chief executive Paul O’Callaghan said this response was in stark contrast to that of the Western world during the Ethiopian famine of 1984.

Then, thousands of Australians took action and made donations as part of the Live Aid concerts to end poverty and hunger.

“This time the scale is larger but it is just not on our radar,” O’Callaghan said.

In fact, it’s been described as the worst humanitarian disaster since WWII.

O'Callaghan had recently returned from Kenya where three million people are at risk of death from starvation. He told Fairfax he witnessed the devastation first hand, seeing many malnourished children.

"Those kids will probably be dead by the end of the year," he told The Age. "It's looking extremely bleak."

"We just haven't found - even across our normal donor base - there was much awareness of this even though we know our donors have very big hearts and would normally respond to something like this."

The Turnbull government has pledged about $68 million in funding this financial year towards providing emergency food, healthcare, water and sanitation to people in affected nations.

And while that's a start, so much more funding is needed to save the millions of lives that are threatened, according to aid agencies like Caritas.

The message is clear: if we're going to save lives, we need to act now.

-With AAP

If you would like to help, you can donate to:

• Caritas Australia's Africa Emergency Appeal. 
• UNICEF's appeal to Stop Famine. Save Lives.
• Australian Red Cross' East Africa Food Crisis Appeal.