An investigation by the Australian Communications and Media Authority (ACMA) has led to TPG being hit with a AU$360,000 fine for breaching the Spam Act.
The ACMA investigation began after complaints from consumers that TPG was not unsubscribing customers from SMS spam after they asked to be removed.
"Consumers have a right to expect that their requests to unsubscribe from marketing messages will be respected," ACMA Chair Nerida O'Loughlin said in a statement.
"This is a timely reminder to anyone who conducts email or SMS marketing to make sure the systems they have for maintaining their marketing lists are working well and comply with the Act."
ACMA said people who are receiving spam and would like it looked into can forward SMS spam to 0429 999 888, or forward the message to email@example.com if it's email spam.
TPG was able to avoid Federal Court proceedings by cooperating with the ACMA, admitting fault, and remedying the issue.
The fixed broadband giant is currently in the midst of deploying a pair of its own mobile networks in Australia and Singapore.
In September, the company said it had made "strong progress" in both nations, with the Australian network to cover Sydney, Melbourne, and Canberra by June 2018.
"In Australia, where the initial network implementation is concentrated on the country's most densely populated areas, the group has already entered into agreements with multiple partners to gain access to a large volume of sites to provide coverage of major metropolitan areas," the company said at the time.
"TPG's strategy is to deploy a primary small cell network across metropolitan areas, complemented by a traditional macro network."
At the same time, the company said it expects to complete its Singaporean network by December 2018.
The company has previously predicted a capex spend of between SG$200 million and SG$300 million for the rollout of its Singaporean mobile network.
For the financial year, TPG announced net profit of AU$413.8 million, up 9 percent from AU$379.6 million a year ago, on revenue of AU$2.49 billion, up 4 percent.
Earnings before interest, tax, depreciation, and amortisation was AU$890.8 million, up 5 percent from AU$849.4 million.
Related TPG Coverage
TPG and Amaysim's Vaya have joined Telstra and Vodafone in a mobile plan refresh ahead of this week's Apple iPhone announcement.
The telco believes the base for rural NBN tax is too low, and everyone should pay, including over-the-top service providers.
TPG has raised AU$320 million of the AU$400 million it is seeking to help fund its AU$1.9 billion mobile network across Australia, with primary shareholders including CEO David Teoh providing most of the contribution.
TPG said its AU$1.6 billion mobile network across Australia will provide coverage for 80 percent of the population, and will be rolled out over three years starting in 2018.