WhatsApp users across Ireland and Britain have been warned to ignore messages offering cash giveaways after scammers took control of the messaging app to trick people into handing over personal information.

Messages seemingly sent by the Argos retail group have appeared on numerous mobile phones across Ireland in the last 24 hours with offers of free vouchers. Similar messages have also appeared on UK phones from stores including Asda, Tesco, Marks and Spencer and Aldi.

Action Fraud, the UK’s national fraud intelligence bureau, warned WhatsApp users in October that fraudsters were sending out fake Sainsbury’s and Topshop voucher details through personal messages that appear to be sent by a friend or family member.

However, the group warned that the recipient’s name is actually fake and designed to trick you into clicking on the URL in the message. By clicking on the link you are taken to a fake website which can access personal information on your phone.

The Argos message, which began spreading across Irish phones on Monday, claims that the retail group is giving away €500 vouchers to celebrate it’s 31st anniversary. It then invites users to follow a link which appears to link to argos.com.

A similar message claiming to be sent by SuperValu was sent out to Irish phones offering free coupons in mid-October.

A spokesperson for Argos advised customers to “always be mindful of phishing scams. This message is not from Argos and we are advising customers to delete it”.

Action Fraud tweeted on Tuesday that WhatApp messages were now appearing on phones purporting to be sent by Nike, Lidl and Singapore airlines. It advised users not to forward the message to friends.

WhatsApp users who may have clicked on the link and are worried about their personal information are advised to install security software on their device and keep it up to date. WhatsApp users can also contact the company to report security issues through the app settings on their phone.

Last year, numerous WhatsApp users were tricked into downloading a fake version of the messaging service which infected Android devices with malware. The ‘WhatsApp Gold’ service sent messages to people’s inboxes inviting them to join the new exclusive service, according to Action Fraud. The scam also claimed to offer enhanced features used by celebrities.

WhatsApp has said they will never send users a message asking them to upgrade or download another app.