Australia's dominant telecommunications company Telstra yesterday warned of "enormous challenges" ahead as it posted an 8.9 percent slump in annual profit, reports AFP from Sydney.

Its net result in the year to June 30 fell to Aus $3.52 billion (US$2.54 billion), while revenue was flat at Aus $26 billion.

Chief executive Andy Penn said intense competition for mobile customers and increased customer expectations were having an impact on business.

"Companies are defined by how they respond in challenging times and there is no doubt Telstra, and the telecommunications industry globally, is operating in times of enormous challenge and change," he said.

"On one hand demand for our core products and services continues to grow. Telecommunications networks have become some of the most important pieces of infrastructure in the world today.

"On the other hand, competition has never been more intense, our market dynamics are shifting rapidly, and customer expectations are changing."