Telstra has been ordered to pay $A18.55 million for anti-competitive behaviour.
The Australian Competition and Consumer Commission took legal action against the company for breaches of the Telecommunications Act by preventing rival companies accessing a number of local exchanges.
The commission argued Telstra was legally required to allow access to its infrastructure to enable the set up of high speed broadband connections.
The court heard Telstra admitted to 27 breaches of the Telecommunications Act.
Justice John Middleton ordered the company to pay $A18.55 million in fines.