Documents leaked via WikiLeaks showed that the Trans-Pacific Partnership agreement will undermine Australia's universal healthcare system, pushing up the cost of medicine, according to media reports on Thursday.

The TPP is a US-led regional Pacific Rim regulatory investment treaty, negotiated in secret, encompassing approximately 40 percent of the world's GDP.

Documents leaked via WikiLeaks showed TPP countries will face a much greater risk of pharmaceutical companies taking legal action to contest government decisions. These actions relate to the list price and reimbursement of medicines, suggesting consumers will pay more while corporate profits will be protected.

The Australian government subsidizes the cost of pharmaceuticals for every Australian.

The newly disclosed draft, dated December 2014, has been changed from previously leaked US proposals. The new text is largely based on compromises developed by Australia and Japan in consultation with the United States.

Deborah Gleeson, an expert in international trade and public health at La Trobe University, in Melbourne, said although the draft was significantly watered down from previous versions, the new version is clearly intended to "cater to the interests of the pharmaceutical industry".

"It sets a terrible precedent for using regional trade deals to tamper with other countries' health systems and could circumscribe the options available to developing countries seeking to introduce pharmaceutical coverage programs in the future," Gleeson said.

Gleeson said the reference to an investor-state dispute settlement mechanism in the leaked draft would allow multinational corporations to sue countries over their pharmaceutical policies.

Matthew Rimmer, a professor of Intellectual Property Law at Australian National University, said the latest leaks highlight a need for open debate on the TPP.

"Obama can only proceed with the trade agreement with the fast track authority from the US Congress," Rimmer said. "There needs to be proper legislative scrutiny by the US Congress and similarly here in Australia."