The 2017 Vinnies CEO Sleepout, launched at Old Parliament House this month, is aiming to get 150 participants and raise $500,000 to fund services across Canberra and Goulburn.

Vinnies Canberra/Goulburn chief executive Barnie van Wyk said the $425,000 raised at last year's sleepout provided 17,000 services and 40,000 meals for those in need.

"It might have been just providing a bed to sleep on," Mr van Wyk said.

"We haven't solved the problem. The ACT has the second highest rate of homelessness in Australia."

Of the 105,000 Australians who experience homelessness daily, more than 1700 were in the ACT.

In Canberra, 500 people experiencing homelessness were under 18, with almost 300 of them aged under 12.

"As proud citizens of this vibrant and diverse city of ours we all have a responsibility to do something about that," Mr van Wyk said.

Former ABC-presenter Alex Sloan said the Vinnies' Clemete program, which provides university-level education to people experiencing hardship, was only possible through funding raised from the CEO sleepout.

"This changes lives," Ms Sloan said. "This is why it's so important."

Menslink chief executive Martin Fisk has taken part in the sleepout since 2011.

"I've been doing this for many, many years. Vinnies do a great job," Mr Fisk said.

Australian War Memorial chief executive Dr Brendan Nelson said Canberra's homelessness rate was a reflection "on all of us".

"If I can spend a night 'sleeping' outdoors, it's the very least I can do," Mr Nelson said.

The Northern Territory has the highest homelessness rate in Australia, while Tasmania has the lowest.

In the ACT, 50 per 10,000 people experience homelessness.

The major causes are accommodation issues or family breakdowns, including domestic violence.