The Information Commissioner's Office has ruled that Bluetooth should be excluded from its Privacy and Electronic Communications Regulations.
Although it has not yet published its reasoning, it has been reported that it was decided Bluetooth technology does not count as a public electronic communications network.
However, the decision has prompted fears that the technology could now be open to unregulated abuse from spammers.
Marketers have now been warned by the DMA that the ICO's exclusion of Bluetooth from its electronic communications guidelines could put the medium in a "technological no man's land".
The DMA has urged the regulator to consider all forms of electronic communication as subject to permission and privacy laws.
The DMA's own Mobile Marketing Council's Best Practice code states that all electronic communications should fall under the ICO's privacy guidelines, and that reversing its stance did not equate with best practice advice.
Nick Fuller, chair of the DMA Mobile Marketing Council, said: "While it is understandable that the ICO sees Bluetooth as falling outside of the PECR legislation in terms of its underlying technology, it is important that the principles of the PECR are not lost.
"I am increasingly speaking to Bluetooth marketers who appreciate the principle of permission and who approach potential applications accordingly but it would be naive to assume that this will always be the case."
Stefan Hohmann, chief executive officer of Bluetooth marketing firm Bluepod Media, told Brand Republic that his company approved of the ICO's decision.
He said: "We welcome the ICO's declaration as a victory for commonsense. Consumers and users of Bluetooth have a clear sense of what the technology is and switching the device on or off on their phone is in effect acknowledging whether the user wishes to receive communications from marketers."
Hohmann said there would always be examples of bad marketing practices, but warned it was up to the mobile marketing industry as a whole to regulate itself, and that "it is clearly not in our interests to spam people".
He added: "A trial by HSBC earlier this year involving Bluetooth marketing in its banks received a very good response from consumers, particularly from the blue rinse brigade, as it gave them an alternative method of receiving valuable information."
The ICO is due to update the PECR shortly, following Bluetooth's removal from its electronic guidelines.