Highly managed trade agreements like the Trans-Pacific Partnership favour big corporates by screwing down workers' wages, says an academic.

Photo: RNZ / Murielle Baker

Harley Shaiken is the chair of the University of California, Berkeley's Centre for Latin America Studies and is in New Zealand as a guest of Massey University.

He said a study of the North American Free Trade Agreement (NAFTA) found while productivity soared, real wages for Mexican workers declined by 20 percent between 1994 and 2011, while Americans' pay fell by 14 percent.

Professor Shaiken said the TPP followed a similar model protecting big corporations and freezing out the rights of workers, consumers and environmentalists.

"Inclusive trade where the rules of the game ensure that consumers, working families, communities share in the gains is very positive for everyone, where the trade is defined so corporations share in the gains in the expectations that gains will trickle down, there we have considerably more problems."

Professor Shaiken said there was a lot of anger in the United States about trade and the TPP, which politicians were tapping into and he expected that the deal will fail in its current form.