The world's two largest economies are not members of the CPTPP bloc, which was established in part as a counterweight to China's growing clout.
US President Donald Trump withdrew the United States from the agreement soon after he took office in 2017.
Other countries want in, including the United Kingdom, which is keen to strike new trading partnerships after its exit from the European Union.
Read also: EU to Trump Administration: Stop US Trade Sanctions Threats
Britain's ambassador to Mexico, Corin Robertson, said the process of accession would take time and no major announcements were expected about the matter during the ministerial meeting.
"It's still very much our intent to join CPTPP. We see it as a great opportunity for the UK as part of a more ambitious trade agenda post-Brexit," Robertson told Reuters on Wednesday.
Japanese Economy Minister Yasutoshi Nishimura told the video conference that Tokyo would welcome new members in the bloc.
"As a matter of principle, Japan welcomes those economies who are willing to meet the high standards of the agreement," he told the meeting.
(Writers: Laura Gottesdiener, Frank Jack Daniel, Kaori Kaneko | Editors: Lincoln Feast Kim Coghill)
Simak breaking news dan berita pilihan kami langsung di ponselmu. Pilih saluran andalanmu akses berita Kompas.com WhatsApp Channel : https://www.whatsapp.com/channel/0029VaFPbedBPzjZrk13HO3D. Pastikan kamu sudah install aplikasi WhatsApp ya.