Millions of people have been sent text messages from scammers posing as Royal Mail in an attempt to intercept their bank details.
The Chartered Trading Standards Institute (CTSI) said the messages claim a parcel is awaiting delivery but a "settlement" must first be paid.
The messages include a link to a fraudulent Royal Mail website which asks the recipient to enter their bank details to release their parcel.
The CTSI warned that the rise in online shopping means more people are likely to be waiting for parcels and deliveries, making them more vulnerable to this kind of fraud.
Lead officer Katherine Hart said: "This delivery scam is yet another example of fraudsters attempting to make money out of the unsuspecting public. Due to the lockdowns, many millions of people rely on product deliveries, so scammers have focused their efforts on this theme.
"Royal Mail will only ever contact you via text or email if a customs fee is due, not for domestic parcel delivery. If you have any suspicions, contact Royal Mail to verify before you click any links or share details.
"Also, the public must also be aware that these types of scams may come in many forms, and scammers do not only use Royal Mail branding.
"Indeed, in January, I commented on a similar scam that used DPD branding.
"These types of scams come in many forms, not just via text but also in emails and through the phone."
People are encouraged to report scams to Action Fraud, or for email scams contact the National Cyber Security Centre by emailing report@phishing.gov.uk.
Be scam aware - how to protect yourself
Don't assume anyone who's sent you an email or text message – or has called your phone or left you a voicemail message – is who they say they are.
If a phone call or voicemail, email or text message asks you to make a payment, log in to an online account or offers you a deal, be cautious.
If in doubt, check it's genuine by asking the company itself. Never call numbers or follow links provided in suspicious emails; find the official website or customer support number using a separate browser and search engine.
Spot the signs
Their spelling, grammar, graphic design or image quality is poor quality. They may use odd 'spe11lings' or 'cApiTals' in the email subject to fool your spam filter.
If they know your email address but not your name, it'll begin with something like 'To our valued customer', or 'Dear...' followed by your email address.
The website or email address doesn't look right; authentic website addresses are usually short and don’t use irrelevant words or phrases. Businesses and organisations don’t use web-based addresses such as Gmail or Yahoo.
