FINDERS keepers - but the people who picked up wads of money that fell by the Western Ring Rd this week may end up weepers if they don't hand it in.

There was speculation the money - mainly $100 and $50 bills - was part of a $22,000 load from an armoured car.

Police warned that it is a crime, theft by finding, to keep the money.

Witnesses said they were driving along the freeway near Keilor East on Thursday night when they saw money flying like confetti.

They saw $50 and $100 notes sweeping across the road before the Milleara Rd exit in Keilor East.

One man, who wished to remain anonymous, said he entered the cloud of cash just after 6.30pm.

"It was like driving through a cloud of confetti," he told Fox FM.

"I reckon it would have hit the road 10 seconds in front of me. It was just flying through the air. I pulled over and found about $300 within two steps."

Six other passers-by pulled over and together the group peeled cash off the road for four hours.

He said he collected $8400, while other people at the scene informed him they had pocketed up to $12,000.

Moonee Valley CIU detective Sen-Constable Cameron Ryan warned that people who had pocketed cash faced substantial penalties if they failed to give it back.

"It is an offence not to bring the cash into the police station," he said.

Assistant Commissioner Steve Fontana also urged those who found money to give it back.

"It is a criminal offence," Mr Fontana said.

"We need those people to come forward and hand the money in to police and assist with our investigation."

Keilor Parks Daniella Laganga, 28, said she was driving towards the Milleara Rd exit and had also seen the floating paper but didn't realise it was money.

"I thought nothing of it. There was a bit of traffic in the area and I had run over something on the ground which nearly busted my tyre," she said.

"But even if I knew it was money I don't know if I would have stopped. I would have been scared."

Originally published as Loose cash a highway to strife