Telstra took action against the Federal Government, as well as the Australian Competition and Consumer Commission (ACCC) and 11 telecommunications companies.
The telco argued that giving its competitors access to its equipment amounted to an acquisition of its property.
Telstra said that this acquisition had to be on just terms as stipulated in the Australian Constitution.
In a unanimous ruling, the High Court has dismissed the case.
The court ruled that the access regime set out in the Trade Practices Act did not mean that Telstra's property was being acquired.
Telstra spokesman Jeremy Mitchell says the ACCC is a rogue government agency which is redistributing the company's investments.
"Under the ACCC's regime, Telstra has to sell some of its services for less than $3, in fact $2.50," he said.
"Now, you can't even get into a taxi cab for that amount.
"The ACCC expects us to deliver broadband on those sort of figures."
The ACCC has welcomed today's High Court ruling.
ACCC chairman Graeme Samuel says the ruling is a significant one which will remove uncertainty.
"What it does is to make it absolutely clear that part 11c of the Trade Practices Act - and specifically its application to the unconditioned local loop service and the line sharing service - is constitutionally valid," he said.abc.net, 6 March 2008