After meeting Tuesday with German Chancellor Angela Merkel, Ardern said several countries have indicated they might want to sign on to the deal, known as TPP, which was signed by her nation and 10 others last month.
U.S. President Donald Trump pulled the U.S. out of TPP negotiations but last week signaled he might reopen talks.
Ardern says if the United States would like to follow through on their interest, that would trigger a renegotiation as it would if others were interested in joining the agreement.
She says it's "not simply a matter of putting their hand up and slotting straight back into the agreement."
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