Fifa will vote on Tuesday on plans to expand the World Cup to 48 teams from 2026, in line with the vision of president Gianni Infantino.
The Swiss, who claims to have "overwhelming" support for the plan to increase the number of teams at the finals from 32, favours 16 groups of three countries, with the top two progressing to the knockout rounds.
If successful, it would lead to the first World Cup expansion since 1998.
There are five options world football's governing body will consider.
The expansion options
Infantino, 46, succeeded fellow Swiss Sepp Blatter as Fifa president in February 2016, having campaigned on a promise of expansion.
The former general secretary of Uefa [European football's governing body] initially suggested a 40-team tournament - an idea put forward by then-Uefa president Michel Platini in 2013 - before shifting focus to a 48-nation finals.
The five options the 37-member Fifa council will choose from are:
- A 48-team World Cup consisting of 16 groups of three, with the top two sides qualifying for a last-32 knockout stage (80 games in total);
- Another 48-team version consisting of a 32-team, one-game knockout round, with the winners joining 16 already-qualified teams (80 games - 16 in preliminary and 64 in main tournament);
- Expanding it to 40 teams, with 10 groups of four and only six group runners-up advancing (76 games);
- A 40-team tournament with eight groups of five (88 games);
- Keeping the World Cup at its present size of 32 teams (64 games).
In Infantino's favoured option, the number of games rises from 64 to 80, but the finals can still be played within the existing tournament duration of 32 days, while a nation will play no more than seven matches, as in the present format.
One potential flaw is that penalty shootouts may have to be introduced to settle drawn group matches to prevent two sides playing out a result in the last round of games that ensures both countries progress.
Speaking at a sports conference in Dubai in December, Infantino said the World Cup has to be "more inclusive" and that expansion will also benefit "the development of football all over the world".
He added: "There is nothing bigger in terms of boosting football in a country than participating in a World Cup."
Despite saying "the decision should not just be financially driven", Infantino did highlight the possible financial upsides.
According to Fifa's own research, revenue is predicted to increase to £5.29bn for a 48-team tournament, giving a potential profit rise of £521m.
Who is in favour of expansion?
Infantino has said that Fifa's 211 member federations are "overwhelmingly in favour" of a 48-team tournament, with the bulk of the 16 extra places expected to go to Africa and Asia.
England, Scotland, Wales and Northern Ireland are all reportedly expected to back the expansion, as long as Europe is offered guarantees of extra spots.
Fifa is not planning to allocate the extra slots at Tuesday's vote. Europe currently has 13 places which could potentially rise to 16 with one European country in each group.
Scottish FA chief executive Stewart Regan has said that expansion is "a positive thing for the smaller nations", citing the performances of Wales, Iceland and Northern Ireland in the expanded 24-team Euro 2016 tournament.
Venezuelan Football Federation president Laureano Gonzalez has reportedly said that Fifa has proposed merging the North and South American qualifiers for a 48-team World Cup in 2026.
Gonzalez, who is also vice-president of South American governing body Conmebol, said that any support for the idea would depend on increasing their current combined share of seven places.
"If this went up to 14, similar to what Europe has for more or less the same number of teams, the idea would catch on," he added.
Who is against expansion?
While Britain's Fifa vice-president David Gill is expected to support the expansion plan, English Football Association chief executive Martin Glenn says the organisation would prefer to retain the current format.
"I can't influence Fifa - we're one voice out of 211," Glenn told BBC Radio 5 live Sportsweek.
"Our preference would be to keep the tournament smaller, because there's a quality factor here. But we'll try to influence the shape of it."
The main opposition so far has come from Germany, with football federation president Reinhard Grindel arguing that adding more teams could "strengthen the imbalance" seen at some tournaments.
The European Club Association (ECA), which represents the interests of the top club sides in Uefa, is also against the proposals, saying that an expanded tournament will mean more call-ups, injuries and congestion in the fixtures calendar.
"In the interest of the fans and the players, we urge Fifa not to increase the number of World Cup participants," said ECA chairman and former Germany international Karl-Heinz Rummenigge.
"Politics and commerce should not be the exclusive priority in football."
History of World Cup overhauls
|1930 Uruguay||13||1 group of 4 and 3 groups of 3, with only top team progressing to semi-finals|
|1934 Italy||16||Straight knockout tournament|
|1950 Brazil||15 (although only 13 took part)||3 groups of 4 and 1 group of 3, with top side progressing to final group of four|
|1954 Switzerland||16||4 groups of 4, but only 2 games in each group, with top 2 sides through to quarter-finals|
|1958 Sweden||16||4 groups of 4, this time with 3 games. Top 2 sides through to quarter-finals|
|1974 West Germany||16||4 groups of 4 but now followed with 2 groups of 4, the 2 top sides competing the final|
|1982 Spain||24||6 groups of 4 followed by 4 groups of 3, the winner of each qualifying for the semi-finals|
|1986 Mexico||24||6 groups of 4, top 2 sides and 4 best 3rd-placed teams qualifying for round of 16|
|1998 France||32||8 groups of 4, top 2 sides progressing to knockout rounds|