The US won't need to rejoin the Trans-Pacific Partnership if the "toxic" rules they insisted on, including around affordable medicines, are kept according to a New Zealand law expert.
Trade Minister Todd McClay is currently in Japan with Prime Minister Bill English where the future of the TPP is expected to feature heavily during meetings on Wednesday.
The US withdrawal from the original agreement has left Japan as the largest partner economy.
Trade ministers from the remaining 11 original partner nations are reportedly expected to meet in Vietnam this weekend to adopt a statement committing them to implementing the TPP by the end of the year.
Auckland University professor Jane Kelsey understands the intentions are to adopt the agreement in its existing form.
"Unbelievably they plan to retain the existing text, with all the toxic rules the US insisted on that undermine affordable medicines, grant foreign investors special rights to enforce offshore, prohibit requirements for data to be held onshore, and more," she said.
She questioned why the US would re-joining the agreement, as Mr English has indicated it is hoped they would, if they benefit from the rules without paying for them.
Mr McClay says in its present form whether the US is a partner to the agreement or not they will find some benefit from changes around Pharmac sharing information.
"So any country-specific changes around pharmaceuticals they wouldn't [benefit from] unless they were part of TPP, but if TPP was to go ahead in its current form they and other countries who aren't part of TPP as it was originally written would find some benefit," he told RNZ.
Mr McClay says it was not unusual for non-partner nations to get some benefit from trade deals.