Aso told reporters in Tokyo that an agreement among the TPP-11 would be a "good thing" for global trade.
Ministers from the 11 countries met in Danang, Vietnam on the sidelines of the Asia Pacific Economic Cooperation (APEC) summit to discuss how to proceed with a TPP deal after the United States withdrew this year.
Asked if an agreement among the TPP-11 will make it easy for the United States to return to the pact, Aso said: "I don't know how the United States feels, but the TPP was originally formed upon U.S. agreements. When it comes to discussing this or that, it's the U.S. turn to join."
"The United States had originally agreed on the TPP as it was not a bad thing for America."
Chief Cabinet Secretary Yoshihide Suga declined to comment on how Japan would be involved in letting the United States return to the TPP, saying that a final agreement on the TPP-11 should wait until TPP leaders' meeting that kicks off later Friday.
Mexico's trade minister said on Thursday the TPP countries had reached agreement in talks, but he gave no details and said there would be an announcement on Friday.
(Reporting by Tetsushi Kajimoto and Kaori Kaneko; Editing by Chang-Ran Kim and Richard Borsuk)