The web host and domain name registrar, owned by MYOB Australia E1, was the subject of an undisclosed number of complaints over emails sent without consent and a functional unsubscribe option.
A MYOB spokeswomansaid that a "small technical problem meant the unsubscribe feature on SmartyHost.com.au was not working.
"The issue has been corrected and we worked with ACMA to ensure all concerns were addressed," the spokeswoman said.
"We regret that this occurred. It was not our intention to spam customers of SmartyHost.com.au, as we always seek to communicate to customers in accordance with their wishes."
ACMA said it was of the view that SmartyHost contravened the spam act "on a number of occasions."
SmartyHost parent company MYOB Australia E1 has entered an enforceable undertaking.
The company paid ACMA $8000 and will develop training programs, quality assurance processes and a complaints-handling policy for electronic communications.
The latter requirement included submitting reports to ACMA over the next year that detailed "any complaints received about commercial electronic messages... and the response to those complaints."
According to ACMA, "the spam act establishes that consent to receive commercial electronic messages is considered to be withdrawn five business days after any request to unsubscribe or opt out".
"This undertaking shows MYOB Australia E1's willingness to establish and maintain an appropriate standard of communication with its customers and sends yet another strong signal to businesses about their legal obligations when sending out commercial electronic messages," ACMA chairman Chris Chapman said.