EMMA ALBERICI, PRESENTER: In Australia, no-one outside the Government has seen the text of what's being negotiated for the TPP.

But Trade Minister Andrew Robb says over the past four years, there've been more than 1,000 briefings with stakeholders and the public will have months to look at the detail of the deal before it's ratified by the Parliament.

Our political correspondent Tom Iggulden has the story.

TOM IGGULDEN, REPORTER: Free trade's been a winner for the Government so far, three deals signed with major trade partners in its first year in office.

Now the TPP looms as an even bigger trophy in the Coalition's free trade cabinet.

Exporters support the deal, saying it'd seal new trading partnerships and build on existing ones.

ANDREW HUDSON, EXPORT COUNCIL OF AUST.: Ultimately, Australia is a fairly mature market when it comes to services, when it comes to goods in terms of local consumption and production. So we really need to look outside of that - outside of our borders to increase that trade.

TOM IGGULDEN: But outside of business circles, support for the deal dissipates.

GED KEARNEY, ACTU: There are community groups, there are church groups, there are a very wide range of people who have very serious concerns about the TPP.

TOM IGGULDEN: Those concerns escalated with the most recent WikiLeaks revelation of the confidential text of a controversial chapter of the draft deal. It includes what's called an investor-state dispute resolution clause, giving multinational corporations a way to get compensation for government decisions that affect their bottom lines.

KYLA TIENHAARA, AUSTRALIAN NATIONAL UNI.: We can see that Australia is still holding out on not agreeing to have ISDS apply to Australia, but there's a little - now there's a little footnote there that basically shows that the Government is willing to negotiate on that point.

ANDREW HUDSON: Yes, we probably will have one. I don't perceive it as being as difficult - or the Export Council sees it as a reality.

TOM IGGULDEN: The revelation confirmed the worst-held fears of those who oppose the deal. Investor clauses, it's argued, give the biggest companies on the planet the power to trump governments' ability to pass law and courts' ability to enforce them.

GED KEARNEY: We are against trading away our sovereign rights, we are against trading away our health and our access to medicines, we're against trading away environmental safeguards, our public services and absolutely 100 per cent we are against trading away Australian jobs.

TOM IGGULDEN: Last year the country's top judge gave a speech about the potential impact of investor clauses, saying, "My concern is with the judicial system and its authority and finality of its decisions ...". In Chief Justice French's words, investor clauses raise, "... potentially serious questions about the interaction of such an award with the domestic judicial system which may be called upon to enforce it."

ANDREW HUDSON: I don't see it being as comprehensively ad a problem as perhaps others might perceive. The reality is our courts still have jurisdiction over the majority of issues. The Government still has a jurisdiction over the majority of issues.

TOM IGGULDEN: Supporters of the TPP point to investor clauses in the recently-signed trade deals with China and South Korea. They aroused little controversy amid the expectations of new export opportunities.

Labor raised objections, but ultimately supported the deals.

GED KEARNEY: And I've gotta say we were actually very disappointed that Labor didn't step up, actually, and try and try to push back much harder on those things through the parliamentary process.

TOM IGGULDEN: Investor clauses been increasingly common in free trade deals signed around the world over the last decade and so too have the number of legal cases against governments. About 550 are currently active by one estimate.

Pharmaceutical giant Eli Lilly's suing the Canadian Government for half a billion dollars over its drug patent rules.

Resources company Lone Pine is suing the Quebec Government for banning fracking in an environmentally-sensitive river valley.

Australia's being sued too by cigarette maker Philip Morris, which is using an investor clause in old free trade agreement with Hong Kong to sue Canberra for damages over the Gillard Government's plain-packaging legislation.

John Howard's negotiating team successfully fought to have a proposed investor clause removed from the free trade deal it signed with the US a decade ago.

MARK VAILE, TRADE MINISTER (2004): The investor state dispute mechanism does not exist in this agreement. This was an issue that was raised by the United States, but it was an issue that we knew if we agreed to this in this agreement that there would be - no state government in Australia would support this agreement.

TOM IGGULDEN: The TPP puts an investor agreement with the US back on the table.

ANDREW HUDSON: We can't accept to have our own way with these agreements. The important thing then is the terms of those state dispute resolution provisions, what is included and what is excluded.

TOM IGGULDEN: The Government's signalled it'll fight to exclude heath regulations from a deal, but exactly what else is up for negotiation is only known by a select few.

KYLA TIENHAARA: Particularly in the United States, there are ways for corporations, large corporations that have a vested interest in, for example, investor state dispute settlement, gaining access to the negotiating texts and knowing what's going on and therefore being able to influence what's going on.

TOM IGGULDEN: The Trade Minister's accusing opponents of the deal of distorting and misrepresenting concerns about investor clauses to undermine public confidence in the TPP. His office told Lateline, "there's very little to fear," adding there'd be safeguards to protect Australian law in anything the Government signs up to.

KYLA TIENHAARA: The problem is is that the safeguards as they currently stand are not sufficient. They've been used by the US for the past decade and it has not stopped cases from developing.

ANDREW HUDSON: I don't subscribe to the view that government would commit us to anything or negotiate for anything which would be adverse to the national interest. We have a fairly rigorous review mechanism and I don't think we'll see anything particularly adverse to us.

TOM IGGULDEN: But just where the national interest lies is a grey area for many in the TPP debate. One internet freedom advocate worries about how the deal could affect protections for personal data like that included on a loan application to a bank.

JOHN LAWRENCE, ELECTRONIC FRONTIERS AUST.: I think most people would reflexively say should this sort of data, should highly personal, highly sensitive information, should the Australian Government be able to pass a law to say that this has to be hosted in Australia? Yes, I think we should. And there's a good chance that the TPP will stop that.

TOM IGGULDEN: And that, he says, could expose Australian citizens' data to the rules in other jurisdictions.

JOHN LAWRENCE: It is then potentially at the whim of the local privacy laws. So, for example, the best - probably the best example is the US, where any data hosted in the US is subject to the US Patriot Act, which essentially gives law enforcement there more or less carte blanche to do anything they want.

TOM IGGULDEN: So we could have, thanks to the revelations of Edward Snowden, the NSA for example in the States looking at Australian metadata.

JOHN LAWRENCE: Absolutely.

TOM IGGULDEN: That's a concern, isn't it?

JOHN LAWRENCE: Certainly.