The coronavirus pandemic is one of the most challenging times most Australians have faced, but not so for Joachim Hirschfeld, who escaped the Holocaust and has today marked his 100th birthday.

He was born to Jewish parents in Germany just after World War I but managed to flee the Nazis despite getting a postcard from the Gestapo.

"The postcard said 'we command you on the Tuesday morning at 10 o'clock on the railway station, packed with overalls'," he said.

"But I said one thing: 'Without me. I'm not going' because I knew what they wanted."

Mr Hirschfeld's parents were killed in the Holocaust, but he fled on foot, walking through France and then finding sanctuary in Switzerland.

He met his wife there and they eventually migrated to Australia with their young family.

Joachim Hirschfeld (second from right at the front) in 1939 at a farm youth camp in The Netherlands, where he was sent before fleeing the Nazis. ( Supplied: Joachim Hirschfeld )

Mr Hirschfeld's daughter, Heidi Kowalski, said his example showed people could survive though adversity.

"He survived through the most horrendous obstacles and experiences through his life to come out the other end as the winner, having a huge, wonderful family, a wonderful, positive attitude, a huge sense of humour," she said.

She said her father was "the true definition of a mensch", a Yiddish word for a honest and highly-principled person.

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Pandemic curtails big bash

Mr Hirschfeld's 100th birthday celebrations were not been the party his family had planned.

Joachim Hirschfeld greets great-grandchildren George and Francesca outside the window of his aged care home ahead of his 100th birthday. ( Supplied )

With four children, seven grandchildren and nine great-grandchildren spread across Australia and the world, the party would have doubled as a family reunion.

Instead, those who live in Adelaide held a small celebration in the courtyard of his eastern suburbs nursing home while keeping their distance.

"We thought 'we've got to do something. We can't just let him think that we don't care'," Mrs Kowalski said.

"We were very lucky [the nursing home] let us come here, as long as we kept our social distance, which we're trying to do."

The party was a surprise to Mr Hirschfeld, who was also presented with letters from the Queen and the Prime Minister.

"Everybody was telling me they can't come from Sydney, from Brisbane, so what are you to do?" he said.

"It's wonderful, very ingenious."

At his celebration, Mr Hirschfeld gave his advice for a long life.

"Healthy living — no smoking, no drinking, no nothing!" he said.

"Do nothing" might be the most important advice, as people try to get through the coronavirus pandemic.