Normally priced at $10 per user per month for mail and web security, Xero customers pay $8 and partners receive a generous 50% discount (ie, $5).
"MailGuard is already used by numerous top tier accounting firms, and is not only a reliable and affordable technology, but also a thought leader in the internet security space," said Xero Australia managing director Trent Innes.
"The rapid escalation of cyber-crime means email and web security is a daily challenge for business of all sizes," said MailGuard founder and CEO Craig McDonald.
"It takes valuable time and focus away from the business of running a business — from C-suite executives right through to front line staff in security, finance and IT departments.
"A common assumption is that traditional anti-virus software is sufficient in preventing an attack, but that's simply not the case.
"Working with Xero means we will now be able to protect more businesses against emerging threats, and free up time and resources that are currently tied up dealing with these attacks every day."
MailGuard claims that testing shows its service is between 2 hours and 48 hours ahead of the market in preventing new attacks.
Xero partners and customers can register their interest in the MailGuard offer here.