Supermarket chain Asda has warned customers not to open emails purporting to be from the retailer as it may be a scam seeking to collect personal information.

Emails circulating among some Asda shoppers are entitled “You have received a gift card from us”, though the grocer said it was in no way involved in the messages and fears that this could be an attempt to criminally capture private data.

Recipients are told they have won an Asda voucher worth between £50 and £1,000 and The Daily Mail reported that many entered significant personal information including name date of birth and address before being told they had been entered into a prize draw.

Following complaints about the issue, Asda commented on its Facebook page: “WARNING: Do not respond to emails claiming to be from Asda with the subject:”You have just received a gift card from us”.

“These emails are nothing to do with us and may be an attempt to capture your personal information. Please warn your friends.”

Earlier this year, the British Retail Consortium published an e-crime study which found that online crime cost the retail sector £204.5 million in 12 months with personal identification-related frauds causing a loss of £20 million in 2011-12.

An Asda spokesperson told Retail Gazette: “we have had reports of an email doing the rounds concerning a free gift card being offered by Asda Direct, this has not been sent from Asda and we believe this to be a Phishing Email.

“We are asking all customers to ignore and delete any email with the subject ‘You have just received a gift card from us‘ as this may be an attempt to capture personal information.

“Our Marketing Team is aware that this email is in circulation; however this has nothing to do with Asda.

“We would never ask our customers to give us their banking details via a marketing communication.”