The AFC announced that its Professional Football Committee had adopted changes to the competition that will see the 2026/27 edition of the club championship feature 32 teams, up from 24 at present, when it kicks off in September.
Japan currently have three automatic berths in the league phase while Saudi Arabia have two plus a playoff place.
Organisers have increased Saudi Arabia's quota of guaranteed berths to three - in line with the Japanese - while granting the two countries an additional two playoff slots.
Japanese and Saudi Arabian clubs have dominated the competition since the adoption of the new format in 2024 with Saudi Pro League side Al-Ahli due to meet J-League outfit Machida Zelvia in the latest final on Saturday.
The expansion will see the league phase in both west and east Asia grow from 12 to 16 teams on each side of the confederation with the first eight finishers progressing to the knockout rounds next season.
The United Arab Emirates have also seen their allowance increase to three automatic slots with one playoff place available while Qatar have been granted three confirmed berths.
South Korea have been given one additional playoff spot to their existing three confirmed places while Thailand have seen their quota increase from one to three guaranteed league phase slots.
China retain their two automatic spots but lose a playoff place after all three of their participants failed to advance to the knockout rounds of the current edition.
Australia have had a playoff slot added to their one confirmed place in the league phase while Jordan and Vietnam have both been given playoff places.
The decisions are subject to ratification by the AFC's executive committee.