"In many ways, it is worse, as the cost of marketing is shifted almost entirely to the target, and the method of communication is more intrusive," she said.

"ACMA has closely scrutinized the missed call marketing practice to determine whether it is in breach of the antispam legislation. We believe that it is, and would like to send a clear message to the public and the industry about the legality of this practice.

In the first and most prevalent example of missed call marketing, callers were told about a gift of mobile content that they could receive by calling a 1900 premium rate number.

In a more recent example of this type of marketing, callers were advised of a mobile premium SMS-based dating service operated on a '19' number.

Complaints can be lodged via ACMA.