Australia's media union is again demanding uniform shield laws across the country after billionaire Gina Rinehart was ordered to pay the costs of Fairfax journalist Adele Ferguson following a failed attempt to force her to reveal her sources.

Ms Rinehart and her Hancock Prospecting company had been pursuing Ms Ferguson via subpoena after she wrote an unauthorised biography about Ms Rinehart.

The demand for access to Ms Ferguson's source material for the book and other articles was thrown out. And in the West Australian Supreme Court on Friday Justice Janine Pritchard awarded the journalist the right to apply for any special legal costs.

After the legal victory, Christopher Warren, the federal secretary of the Media Entertainment and Arts Alliance, said the principle of protecting journalist's sources needed to be enshrined nationally.

"That will require uniform national shield laws, which is not the case at the moment," Mr Warren said.

"These ... cases, despite their welcome outcome for our members, clearly demonstrate Australia's patchy and disparate journalist shields fail to do their job.

"It is appalling journalists are served with a subpoena that essentially would require them to breach their ethical obligations."

In a landmark judgment by the WA Supreme Court last year, Justice Pritchard set aside a subpoena from Ms Rinehart served on Gold Walkley winning reporter Steve Pennells, which could have landed him in jail.

Pennells and his employer, The West Australian newspaper, fought Ms Rinehart's legal demands for more than 18 months.

Justice Pritchard said the subpoena should be set aside "on the ground that it is oppressive and an abuse of process".

"There is a deficiency in Australia's shield laws if powerful people with deep pockets can continue to drag journalists through a series of legal procedures in an effort to disclose information," Mr Warren said.