A Sydney woman is looking for answers after having to save her neighbour's cat from an animal trap left in a suburban street.

Dana Kouris was checking the mailbox earlier today when she heard a cat screaming in her driveway in Canterbury, in the city's inner-west .

She found her neighbour's pet had its leg caught in a spring-loaded animal trap .

The cat was trapped in this device left on a street in Sydney's Canterbury. (Dana Kouris)

She and her husband then had to figure out how to get the rusty device off the cat's leg.

"I got the position of holding the cat down, and my husband had the job of working out the mechanics of getting it off," she told 9News.com.au.

"It was a good five minutes, and the latch comes off, and the cat just took off."

Ms Kouris suspects the cat may have dragged itself from somewhere else with the trap, but does not believe it could have gone far.

The rusty device was left in suburban Canterbury. (Dana Kouris)

But the bigger question in her mind is why would someone do this?

"We're just a normal suburban everyday street," she said.

"It's almost like someone was angry, and doesn't like cats.

"I've never seen anything like it."

It's also a mystery where a person could get such a trap.

The trap had to be dissembled to free the ensnared pet. (Dana Kouris)

"It looks like someone's making these in their garden, but I can't pinpoint a crazy neighbour," she said.

"I can't believe people buy them."

Ms Kouris was fearful not just for local pets but for children returning home from school.

She had to get a tetanus shot because of the bites and scratches she received while trying to help the cat.