Police have issued a warning over a new scam involving cryptocurrency 'wallets' which they say are being scattered on streets and in parks around New South Wales.

NSW Police say they've have reports of people being scammed out of cash by falling for a trick left in small paper 'cryptocurrency wallets' they've found.

Designed to look like real paperwork relating to digital currency such as Bitcoin, they include an image of a QR code.

But if the finder picks it up, thinking it might be worth something, and scans the code with their phone, they could see their bank account emptied, police say.

The person is then asked to click on the link to access a crypto wallet, which claims to have up to $16,000 in it

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