Revenue was also down, with $2.5 billion coming in, a 0.7% decrease from FY2018.
The company was forced to cancel plans for its mobile network, which would have been the fourth in Australia, after the Australian Government banned Chinese telecommunications vendor Huawei Technologies from supplying equipment for any 5G networks in the country.
At the half-year point itself, TPG recorded a drop of 76.4% in net profit, with the figure being just $46.9 million compared to the $198.6 million of the previous year.
TPG and Vodafone Hutchison Australia are waiting on the Federal Court for a decision on a merger between the two companies. Announced in August last year, the plan did not find favour with the competition watchdog, the Australian Competition and Consumer Commission.
In its results statement, TPG said its earnings before before interest, taxes, depreciation, and amortisation had also been affected by the migration of DSL and home phone customers to low-margin NBN services. The EBITDA figure for FY19 was $809.4 million, a drop of 2.1%
Chief executive David Teoh hinted that the next year could also be a bad one, saying: "FY20 is expected to be the year that the Group experiences the greatest financial impact from customer migration to the NBN, with combined headwinds from residential DSL and home phone customers moving to NBN expected to be around $85 million.
"In addition, the annualisation of the deterioration of profitability of existing NBN customers experienced in 2H19 a result of increased NBN wholesale cost per user is forecast to create a further NBN headwind for FY20 of approximately $25 million.
"By the end of FY20, the Group expects to have less than 15% of its residential broadband customer base remaining on ADSL."
The company said it was continuing to build its Singapore mobile network, with outdoor service coverage measured at 99.69% in July.
"Sign-ups to the free service trial continue to be strong (now close to 300,000)," Teoh said. "Feedback on network coverage and quality continues to be positive and the launch of free unlimited roaming to Malaysia and Indonesia has been particularly well received. Free roaming to India will be launched in September 2019."