But at a rally held in New Hampshire yesterday to mark Sanders' endorsement, Clinton, the presumptive Democratic nominee, went beyond the bounds of the party's official platform.
"We're going to say no to a tax on working families and no to bad trade deals and unfair trade practices including the Trans-Pacific Partnership," she said to a raucous crowd, which included many Sanders supporters.
The TPP faced widespread opposition in New Zealand, sparking protests over issues such as pharmaceuticals and its impact on this country's sovereignty.
Member countries had two years to ratify the agreement after it was signed in Auckland in February. However, it will not come into force if it isn't ratified by the US and Japan.
The Labour Party has said it will vote against the TPP legislation.
University of Auckland law professor Jane Kelsey, a leading opponent of the deal, said Clinton's anti-TPP statement was aimed at "playing to the popular audiences".
"She will have been acutely aware of the discussions that took place on the platform and that it doesn't include such a statement," Kelsey said, adding that Sanders was expected to raise the TPP issue again at the Democratic convention later this month.
She said the TPP was unlikely to get the green light from Congress during the lame duck period.
"The Republicans aren't going to want to give [President Barack] Obama a victory, or a legacy," Kelsey said. "The chess game is still playing out and we would expect it to play out probably for another couple of years."
Presumptive Republican nominee Donald Trump also opposes the TPP.
Former trade negotiator Charles Finny, a partner with Wellington-based consultancy Sanders Unsworth, said ratifying the deal during the lame duck session was "the only hope" in the short-term.
"There are risks there," Finny said. "I think it is in everyone's interest to get this ratified during the lame duck period and that's what everyone is assuming will happen."
