Some 1,200 Australian CEOs spent Thursday sleeping rough -- being homeless -- across the country at the 10th annual Vinnies CEO Sleepout.

Vinnies, short for charity St Vincents, provided bare essentials -- a woolen head warmer, sleeping bag, some sheets of cardboard, and a cup of soup and bread for dinner.

The event raises both money and the issue of homelessness in Australia where 100,000 people sleep outside every night.

For vitamin company Blackmores CEO Christine Holgate, the event puts into harsh perspective all those people who don't have a choice.

"Thirty thousand people sleeping homeless tonight are actually children," she told AAP.

"We're fortunate. At the end we'll get up, we might be a bit damp but we'll go home to a nice warm bed. These kids won't."

Women and children make up a large proportion of homeless people, according to Coca-Cola Amatil CEO Alison Watkins.

"(It's) because of domestic violence situations where they feel they have to leave a relationship and they've got nowhere to go," she said, adding that homelessness could happen to anyone.

Communications minister Malcolm Turnbull joined the event and said he's worried homelessness has slipped off Australia's political agenda.

"It is a very real concern and it should be a big priority, and it is a big priority," he said.

"But it's a multi-faceted problem. There are issues, aspects about employment, training, mental health, affordable housing and I think this event ... is an outstanding event because it raises awareness of the issue and also raises a lot of money."

So far 5 million Australian dollars (3.9 million U.S. dollars) have been raised this year through sponsorship for the CEOs who took part in the event. Endi