The free trade agreement begun by New Zealand, Singapore, Chile and Brunei - known as the P4 - two years ago is set to expand even further with two more countries , Australia and Peru, as well as the United States wanting to join.
Other Apec countries will be given a deadline and asked to put their hands ups by March if they want to be part of the next expansion.
The significant development was announced today by Chile Foreign Minister Alejandro Foxley at the Apec trade ministers meeting in Lima, attended by New Zealand's new Trade Minister Tim Groser.
The United States announced in September it wanted in, and Australia and Peru, made their commitments today to join P4, now called TransPac the TransPacific Strategic and Economic partnership.
Vietnam has also expressed an interest but has not yet committed to negotiations to join.
Other Apec countries will be invited to decide whether to join by March, when negotiations for the expanded trade pact will begin.
Asked whether the new United States Administration would be likely to continue with the negotiations after Barack Obama is sworn in in January, United States Trade Representative Susan Schwab told a press conference she expected it would.
"These negotiations will be launched in March and it will be up to them to proceed.
"The United States has a proud and successful history of having a truly bipartisan trade policy dating back to the Roosevelt Administration and 1934 and it is our hope and expectation that they will continue with that, in that spirit."
She said the Obama Administration had "articulated an interest in high quality trade agreements. They have articulated an interest in trade relations with Latin America and the Asia Pacific region."
Mr Groser told reporters that there was no doubt that the international economic turmoil had focused people's minds and referring to the Doha round said "and now what we want to see is the same political dynamic occur in Geneva over the next few weeks."