A new 36-team Champions League format from 2024 is set for final approval by UEFA's executive committee on Monday.
A decision had initially been expected on March 31 but was delayed due to some clubs within the European Club Association seeking a greater say on commercial matters for the new competition.
However, meetings of the ECA board and of UEFA's club competitions committee on Friday have cleared the way for the new format to be rubber-stamped. It is understood the differences which led to the first delay have been set aside rather than resolved.
The expanded format is a cause of concern for the Premier League and many other European domestic competitions, while fans' groups wrote an open letter to ECA chairman Andrea Agnelli criticising it on Friday morning.
European football's governing body will also make a final decision on host venues for Euro 2020, with Bilbao, Dublin and Munich the three yet to be confirmed of the original 12.
The Champions League executive committee will vote on whether to do away with the current group system - where 32 teams are split into eight pools of four - and replace it with one 36-team league.
Each team plays 10 matches on a seeded basis - four more than in the current group phase - in a so-called 'Swiss model', previously described as "ideal" by Agnelli in part because it allows the flexibility to add even more matches in the future.
The new format takes the Champions League from 125 to 225 matches, which would create a huge headache for domestic schedulers. EFL chairman Rick Parry says it would be a "major threat" to the Carabao Cup and the Football Association also wrote to UEFA to express its concerns.
The encroachment of the competition into January - usually kept free for domestic club football - is understood to be another concern for the Premier League.
The league's top eight would qualify automatically for the last-16 knockout stage, with the teams finishing ninth and 24th playing off for the remaining eight places.
The allocation of two of the extra four places to sides based on previous European performance has also proved controversial.
A team could still qualify for the Champions League based on 'historic co-efficient' as long as they did enough domestically to finish in a Europa League or Europa Conference League position.
This has led to integrity concerns at Premier League level, where a team finishing seventh could leapfrog teams in fifth and sixth into a more lucrative competition.
Discussions over commercial control of the competition are set to continue, and fans' groups linked to clubs across Europe with ECA board members - including Arsenal and Manchester United - signed an open letter attacking the Champions League reforms, describing them as "a blatant power grab".
"Instead of realising your supposed goal of 'building a successful, sustainable, and socially responsible football industry', you will only make the gap between the rich and the rest bigger, wreck domestic calendars, and expect fans to sacrifice yet more time and money," the letter read.
"All for the benefit of whom? A handful of already wealthy clubs, investment firms, and sovereign funds, none of which have the legitimacy to decide how football should be run. Even most ECA members stand to lose out from the proposed reforms.
"Such a blatant power grab would be indefensible at the best of times, but at the height of a global pandemic, it is nothing more than crisis profiteering - not to mention a stark contrast to the solidarity displayed by fans."