It was a perfect photo opportunity - a former prime minister and other business executives sleeping on the sidewalk. The event was not a reversal of fortunes, but the yearly Vinnies CEO Sleepout which aims to help the homeless.

Among the participants to the 2012 sleepout were former Prime Minister Kevin Rudd and 157 other business executives from Queensland. Mr Rudd, who also recently resigned as Foreign Affairs minister, slept on the concrete in front of Suncorp Piazza at South Bank.

He slept on just three pieces of cardboard which was lined with a sleeping bag and a pillow.

"Homelessness has been a priority of mine for a very long time and I think it's important for the government to play its role.... But none of it works unless you have got community organisations like Vinnes and others pulling their weight at the top," Courier Mail quoted Mr Rudd.

Vinnies 2012 sleepout, Queensland's third, raised more than $800,000. The Canberra sleepout raised $435,000.

"The reality is you get very little sleep, you may be cold, your back is sore, the cardboard is unfriendly, you hear the garbage trucks coming and you even worry about your own possessions," said St Vincent de Paul Society Queensland Chief Executive Officer Peter Maher.

With 27,000 homeless people, Queensland has the second highest homeless population in Australia.

Another participant in the sleepout was Ayesha Razzaq, the general manager of retailer ActewAGL. She and other executives slept in the Sculpture Garden at the National Gallery of Canberra in Canberra.

"Tonight's just one night - at least I can wake up in the morning knowing I've got a bed to go and somewhere to sleep," Canberra Times quoted Ms Razzaq, who added the experience hopefully gave her a better understanding of what needs to be done to address the growing problem of homelessness in Australia.

To make the night more challenging, the temperature went down to zero and four millimetres of rain poured that night in Canberra.