Former Prime Minister Helen Clark says it would be "unthinkable" for New Zealand to be left out of the TPP, as ministerial talks to try to get the deal signed off this week continue in Atlanta.
Ms Clark met with Prime Minister John Key in New York today and spoke to media briefly.
She rarely comments on New Zealand domestic issues, but made an exception when asked about the TPP, which began under the former Labour Government as the P4 with Chile, Singapore and Brunei.
"What always haunts a Prime Minister is 'will there be a series of trade blocs develop that you are not part of?' Because that is unthinkable for New Zealand as an export-oriented, small trading nation.
"So of course New Zealand has to be in on the action with the TPP and go for the very best deal it can as the agreement expands beyond the original four economies to a wider regional agreement."