Labour activists worry that a US-led free-trade deal under negotiation will prioritise corporate profits over workers' rights and pressure governments to bow to the will of investors.

Trade ministers from the 12 nations negotiating the Trans-Pacific Partnership (TPP) - which would stretch from Japan to Chile and cover 40 per cent of the world's economy - failed to finalise a deal at talks last month on the Hawaiian island of Maui, but were confident an agreement was within reach. Talks are expected to resume in the autumn (NZ spring).

Campaigners for workers' rights complain that they have been denied a voice in the trade talks, and have raised concerns about part of the deal that would allow corporations to sue governments for the potential loss of future profits.

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"The investor-state dispute settlement provisions in this massive trade deal ... if it's passed, binds them to a convoluted logic that allows multinational corporations to sue ... if a government passes a law or regulation that protects its people to the possible detriment of sales," said Shawna Bader-Blau, executive director of the Solidarity Centre.

"Corporate rights are treated as portable, binding and protected by enforceable laws in global trade agreements, but not so human rights," Bader-Blau said at the opening of a migrant labour conference on Monday hosted by Solidarity Centre in Bogor, 60 km south of the Indonesian capital, Jakarta.

Speaking before more than 200 labour and migration experts from 45 countries, Bader-Blau said that while investor rights are protected, human rights are "relegated to unenforceable side agreements, aspirational multilateral protocols, spotty national laws and no accountability".

"Sitting here in Asia, you cannot help but think of slavery on ships, mass graves, the US government's disastrous upgrade of Malaysia in its trafficking in persons report - enormous desperation fuelling enormous wealth," she said.

According to the Office of the United States Trade Representative, the investor-state dispute settlement, or ISDS, is meant to resolve investment conflicts without creating state-to-state conflict, protect citizens abroad, and signal to potential investors that the rule of law will be respected.

"Our goal in TPP is to raise standards across the board, from promoting strong labor and environmental protections to upholding the rule of law", US State Department spokesman Kerry Humphrey said in an email.

However, activists say ISDS has been used to pressure states not to raise the minimum wage or enact labour reforms.

"If we want to protect migrants, we have to tie that to the trade agreements", said Tefere Gebre, executive vice president of the American Federation of Labor and Congress of Industrial Organisations (AFL-CIO). "We think we can go back to the drawing table and draw up a better trade agreement".

Malaysian labour campaigner K. Somasundram says that he has been invited to observe, but not comment during TPP talks with Malaysia's Ministry of International Trade and Industry.

"Why invite us and not allow us to speak?" Somasundram asked on the sidelines of the conference in Bogor.

He worried that Malaysia's "sovereign state power will be given to multinational corporations who will be investing in our country.

"The government has said they are going to take a holistic approach to amend labour laws in line with TPP", Somasundram said. "We fear that they will bow to the demands of capitalists and reduce existing protections in the law."

- Thomson Reuters Foundation