The Australian Competition and Consumer Commission (ACCC) has issued a warning about email scammers this holiday season.

Emails that appear to come from Australia Post or FedEx are landing in inboxes, informing recipients of an “undeliverable package”. The emails look legitimate. They often include a logo, and sometimes information such as your full name and address.

They also include a virus, designed to block access to your computer until you pay a ‘ransom’.

“We encourage customers to visit their local Post Office, or call our Customer Contact Centre on 13 POST if they have concerns,” an Australia Post spokesperson toldMamamia.

“Our staff receive regular training and updates on the importance of vigilance in relation to scams.”

The ACCC’s Scamwatch has received more than 4,300 complaints about email scams in 2016, which is triple the number received last year. According to the ACCC, 350 people have reported providing personal information, including bank account details, in response to scam emails.

There are ways to spot a scam email. (iStock)

“Australia Post will never call you out of the blue to request payment or send you an email asking you to click on an attachment," ACCC Deputy Chair Delia Rickard said in a press release.

"If you receive an email about an undeliverable package, don’t open any attachments or download files – delete it straight away."

If you are unsure whether an email you've received is a scam, the ACCC suggests checking the email address for strange letter and number combinations.

Also, read the content of the email carefully, scanning for errors in formatting or grammar.

Things to look out for, to determine if the email is a scam. Image via the ACCC.

“The email may threaten to charge you a fee for holding your ‘undelivered item’, and will ask you to open an attachment, click a link or download a file to retrieve your parcel," Rickard said.

"If you follow these instructions, you will likely download a ransomware virus that locks your computer.”

Once your computer is locked, the scammers usually demand payment in the form of bitcoins (an online currency) or bank transfer. "Even if you pay the fee, there is no guarantee that you will be able to access your computer again," Rickard said.

Things to remember, according to Scamwatch:

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