A defamation battle between one of the nation's most senior political figures and one of its oldest newspaper publishers has exposed one of the central difficulties of defamation law.

It protects the interests of the wealthy and powerful.

Make no mistake, Treasurer Joe Hockey will be none too pleased with an order that Fairfax pay just 15 per cent of his legal costs of his defamation case against the publisher.

But a well-resourced politician is in a far better position to shoulder his or her own legal costs, which would substantially exceed the $200,000 damages payout in this case, than many would-be plaintiffs seeking vindication of their reputation.

"One of the long-standing criticisms of defamation law is that costs are prohibitive, which means ordinary people are dissuaded from suing in the first place," said media law expert David Rolph​, an associate professor at the University of Sydney.

The Hockey case highlights that the financial costs of a defamation trial – just one of the tolls of litigation – may swamp any damages payout.

But it was also an unusual case because the result was not clear-cut, allowing both sides to claim to be the victor.

"In most cases the plaintiff clearly wins and the defendant loses, so the defendant has to pay the plaintiff's costs," Associate Professor Rolph said.

"This is not your typical case because it's a mixed result. The question of costs became more complicated."

The Treasurer lost his case about a series of articles published in The Sydney Morning Herald, The Age and The Canberra Times but won over promotional material published by two of the mastheads to pique readers' interest in the stories.

Federal Court Justice Richard White said Mr Hockey's submission that Fairfax should pay all of his costs in the SMH and Age cases, in which he was successful in relation to posters and posts on Twitter, was "unrealistic".

"The submission failed to have regard to his failure on the substantive part of his respective claims against the SMH and The Age," Justice White said.

It is a reminder that defamation cases are costly and risky.

But, for his part, the Treasurer says he has no regrets.