Thousands to sleep in cold at MCG

Sleeping on cardboard in chilly Melbourne is not ideal, but thousands will do it willingly to support those who have no choice.

About 1500 people will turn out at the MCG for the annual "Sleep at the G" event on Thursday night, raising money and awareness in a bid to end youth homelessness.

The crowd will sleep on cardboard, and eat soup and rolls for dinner while being entertained by a swag of live acts, including rock band British India.

Melbourne City Mission chief executive Ric Holland says the event, which is in its third year, is expected to raise about $500,000.

He says it is an enjoyable way to get involved in the fight against youth homelessness, a chronic and growing issue that affects about 7000 people under 25 in Melbourne.

"We'll never claim just having a night on concrete at the MCG is a replicator as far a homeless kids are concerned," Mr Holland told AAP.

"It will just remind people these kids are facing conditions worse than this every single night of the week."

The mercury is expected to drop to about 10C overnight.