The ACMA has fined Optus under the Spam Act 2003:
Optus has been slapped with fines of $110,000, the second biggest penalty ever issued under the Spam Act.
The Australian Communications and Media Authority (ACMA) has accused Optus of sending 20,000 electronic messages without accurate sender identification.
Optus says the messages promoted the OptusZoo entertainment service and the company assumed customers would make the link between the sender ID of 966 and its alphanumeric equivalent ZOO.
"Optus assumed that recipients of their messages would make the connection between 966 and ZOO," ACMA Chairman Chris Chapman said.
"However, this was not considered sufficient identification, as '966' could be used to represent any number of permutations on a telephone keypad."
The ACMA says it decided to issue the infringement notices because Optus did not adequately address the issue.