A Perth driver has been caught on camera using what appears to be a nitrous oxide canister.

Shocked commuters spotted the man travelling on Mitchell Freeway yesterday afternoon.

A witness told 7NEWS they saw the driver with the gas bottle - a practice that is also known as doing a nang.

Doctors have previously called for the cannisters to be banned after a growing number of children were found to be using them as recreational drugs.

When inhaled, the gas gives a few seconds of a ‘high’ but its also very dangerous and can stop oxygen to the brain.

WATCH THE SHOCKING FOOTAGE IN THE PLAYER ABOVE

Professor Andrew Dawson said for young people, nangs or ‘bulbs’ were no laughing matter.

“The nerves lose part of their outer sheath, their outer covering, and they no longer conduct signals properly,” he said.

Several Australians have found themselves permanently disabled from inhaling nangs.

Police have attempted to crackdown on them but essentially they are not considered a prohibited drug.

It’s only illegal to supply the cannisters if the seller suspects someone is going to use them to get high.