A US position document on TPP, leaked earlier this year, showed proposals that would "take an axe to NZ IP (intellectual property) law", Shera says - accepting that the leak may have been a negotiating tactic, to take an extreme position from which the US could "gracefully back down" but still achieve major gains.

One reason the US did not achieve what it evidently wanted from ACTA was that discussion was opened up with regular leaks and events such as New Zealand's PublicACTA workshop, in April last year, says Shera.

The TPP negotiations are currently running on the traditional more closed model, he says, and the European Union, both a strong champion of moderate positions and a valuable source of leaks in the ACTA process is not, of course, a party to TPP.

"I'm not one who thinks that each step of the negotiation should be conducted in public," Shera writes. "That only discourages free and frank negotiation or worse still sends the negotiation into informal and far less transparent channels."

The customary treaty-negotiation process, however, "makes a mockery of consultation, the select committee process and of Parliament," he writes.