Growing the cash cow tournament from 32 to as many as 48 teams topped the agenda at this week's FIFA Council meeting.
The powerful 36-member panel weighed proposals for a 40-team competition with eight groups of five teams, or 10 groups of four.
A 48-team format, favoured by Infantino, would see the 16 group winners of a qualifying round automatically book a place in the tournament, while an additional 32 teams would compete in a new pre-tournament play-off.
From the play-off, 16 nations would then move on to the World Cup itself.
FIFA said the council would make a final decision at a meeting on January 9 and 10 .
But there were signs Infantino was winning the necessary support.
"The trend (in the council) is towards a larger format," Belgian council member Michel D'Hooghe said, adding that the allocation of entries among the confederations remained a source of debate.
A council member, who requested anonymity, said the newly crowned head of European football, Aleksander Ceferin, was in favour of a larger tournament.
Critics have voiced concern that a bigger competition would dilute the quality of World Cup play and add new fixtures to football's already packed calendar.
According to the source, some council members were uneasy about the 48-team format but said Infantino "strongly pushed" for it.
Infantino was elected to succeed the disgraced Sepp Blatter as FIFA's chief in February, with a pledge to grow football globally even as the sport's governing body reeled from an unprecedented set of corruption scandals.
On Friday the 46-year-old Swiss-Italian national insisted that any decision to expand the World Cup would be made solely with a view to grow the game.
"The decision on expansion is not a financial or political decision. It has to be a sporting decision. We'll have to decide what is best for football," he said.
The council on Thursday backed plans to allow countries to co-host the World Cup to ease the immense financial burden of organising the tournament.
Bidding for the 2026 World Cup is due to open in the summer of 2017, but a rotational policy will preclude the previous two host confederations -- Europe in 2018 and Asia in 2022 -- from staging the tournament.
The Palestine Football Association had hoped FIFA brass would get tough on Israel this week over six clubs based in settlements in the occupied West Bank.
Palestinian leaders called on FIFA to either expel the clubs in settlements, which are illegal under international law, or relocate them within Israel's recognised borders.
But the council put off making a decision on the thorny issue, as the head of FIFA's monitoring mission for the dispute, South Africa's Tokyo Sexwale, said he was unable to finalise his full report.
Infantino told journalists he would travel to the region, "when it will be meaningful to go, when there is something that is moving in the right way."
Sexwale is due to deliver his report in November at a meeting expected to include both Israeli and Palestinian representatives.
Infantino urged both sides "to come with an open mind, and a constructive attitude."
"We are not a political organisation. We are not here to find political solutions. We are hear to talk football," he said.
Israel's ever-tense ties with the Muslim world also forced FIFA to reassign its next congress, after Kuala Lumpur withdrew as host because Malaysia's government said it would not grant visas to Israeli officials.
The council picked Bahrain?s capital Manama to host the upcoming congress, scheduled for May 11.