A week after a tweet warning people about an ATM hoax went viral, a Croydon police twitter account is at it again.

After "advice" started circulating around facebook telling people that if they were approached by a robber at an ATM machine, to enter their pin numbers in backwards, Croydon MPS took to Twitter to squash the hoax.

"Did you know that if you're being attacked at an ATM, enter your PIN backwards and it'll call the police and a camera will start recording," the account tweeted.

"Neither did we, and that's because you can't. It's an internet hoax and the system doesn't exist.

"Please share to stop the misinformation."

RELATED: Croydon police tweet warning people about atm hoax goes viral

As of writing this, that message has received nearly 6000 retweets.

Four days after that initial tweet went viral, another post has received more than 500 retweets.

"Another common online post suggests that pressing the side button five times on an iPhone 'sends a GPS ping to the nearest station and automatically dispatches officers'," the tweet read.

"In fact, it'll silently dial 999 and you will need to speak with the operator as normal."

All in a hard day's work.