Telstra has been ordered to pay more than $18.5 million in fines for locking broadband competitors out of its telephone exchanges.

In the Federal Court in Melbourne Justice John Middleton found Telstra breached the Trade Practices Act and its licence 27 times between 2006 and 2008.

The ACCC had wanted Telstra to be fined about $40 million, but Justice Middleton said the ACCC had not proved that other companies had suffered any actual losses.

The Australian Competition and Consumer Commission started the case against Telstra after reports the company had told its competitors there was not any room at the exchanges for them to install their equipment.

In fact there was enough space, and Telstra admitted to most of the ACCC's allegations.

The Competitive Carrier Coalition is made up of most of Telstra's main competitors except Optus, and its chairman Matt Healy welcomed today's judgement and fine.

"Unfortunately it merely reinforces that which we know already which is that Telstra really isn't set up to adequately serve its competitors," he said.

"We really need Telstra's cooperation when we try and put our equipment into Telstra's exchanges and other facilities. However, Telstra being our main competitor obviously doesn't have the underlying incentive to give us decent quality of service and really that is what the judgement reflects today."

Justice John Middleton accepted that the requests Telstra rejected in 2006 and 2007 made up only 0.5 per cent of the total number of requests for space that the company received in that time and concerned only seven out of the 526 relevant exchanges.

But Matt Healy says the fact that the case dealt with such a small number of requests does not lessen its significance.

"There are problems obviously in prosecuting some of these cases and bringing all the evidence to court. This has taken more than four years you must remember and, during that time, we see that the conduct is ongoing," he added.

"It really has been a disincentive for investment during that period so, just because on one reading it might not look like many services, the effect of not servicing those people and those customers has undermined competition in quite a significant way."

Associate Professor Caron Beaton-Wells specialises in competition law at the University of Melbourne's Law School and agrees this is a significant case in terms of the extent of Telstra's breaches and the nature of the penalty imposed.

"Telstra admitted the conduct, so it was not a question of whether or not Telstra was liable. The only contest here was between Telstra and the ACCC over the appropriate scale of the penalty. The ACCC did seek a high penalty in the order of $34 million," she said.

"Telstra contended that in fact an appropriate penalty was in the order of $3 million to $5 million so there was a very large gap between the parties on the appropriate penalty.

"Justice Middleton came down somewhere in the middle but closer to what Telstra had submitted was appropriate, in that Justice Middleton ordered a penalty of $18.5 million. He had discounted the penalty that he thought appropriate of $26 million by 30 per cent to reflect Telstra's cooperation essentially in the proceedings."

Professor Beaton-Wells says the case is a significant precedent.

"The primary consideration by the judge in this proceeding was to impose a penalty that would deter Telstra specifically, but other actors in the telecommunications market in the future, from similar conduct and, yes, I do think it is a substantial penalty from that perspective," she said.

"The penalty also reflects the size and the influence of Telstra in the market and the fact that it has significant advantages over its competitors in terms of information and bargaining strength.

"I might say it is also significant that the judge made the finding that Telstra staff really did not have the training or the understanding in their exchange access obligations that they should have had given that Telstra, as I said, has been subject to these obligations for some time, and he found that there was no culture of compliance in the organisation with respect to these obligations."

The costs in the case are still to be finalised.