Recipients find an email with the department's logo attached to the top of the message, asking them for their personal, credit card or banking details in exchange for a tax refund.
However, HMRC has again reiterated that it does not send any emails about tax rebates and has warned people to be careful to ensure they are not the victim of fraud.
According to the department, around 80,000 emails were reported last year alone - showing how widespread the problem is.
But HMRC is working hard to reduce and eradicate the problem, revealing that it took action against more than 500 illegal sites last year alone. This helped stem the flow of emails coming from all parts of the world, including the US, Russia and Japan.
Gareth Lloyd, Head of Digital Security for HMRC, confirmed that the department is doing all it can to protect taxpayers.
"HMRC does not email customers about tax refunds - we only ever contact customers who are genuinely due tax back in writing, by post," he explained.
"If anyone receives an email offering a tax rebate and claiming to be from HMRC, please send it to firstname.lastname@example.org before deleting it permanently. HMRC does everything it can to ensure customers are safe online and we are working closely with other law enforcement agencies to target the criminals behind this serious crime."
Emails often contain link to a clone of HMRC's website, where people are asked to hand over their bank and personal details.
To reduce the risk of being caught up in a scam, the department is advising taxpayers to check advice published on the HMRC website along with forwarding all suspicious emails to its phishing email address.
Phishing emails are more frequent after the January 31st self assessment tax return deadline, according to the department, meaning taxpayers should be on high alert over the coming weeks.
Posted by Thomas Fletcher