A Perth mother has slammed the heartless thief who stole oxygen canisters her premature son needs to live.

TeKao Timu spent the first seven months of his life in a critical condition in intensive care, but is home and requires daily oxygen from canisters to keep him alive.

A man was caught on camera stealing TeKoa's supply from out the front of the family home.

"It's not a normal theft, it is lifesaving equipment – he needs it," TeKoa's mother Madison Dobels told 9News.

Madison wants the thief to come forward and return the stolen cylinders.

"I don't think he'd be aware. I can't imagine someone knowing a kid's on oxygen and taking it," Madison explained.

"You wouldn't be human and if he did know there are no words other than an oxygen thief."

She orders the oxygen twice a week so her son has enough supply, as he can only manage 15 minutes without it before turning blue.

TeKoa only goes without oxygen during fortnightly visits to Perth Children's hospital.

At the time of writing, the thief has not been found and the oxygen bottles have not been returned.

Photo credits: 9NEWS