The proposal would see a playoff round added prior to the group stages, with the 16 defeated nations going home after playing just one match.
From then on, the remaining 32 teams would progress through the tournament as usual.
"The idea is that 16 teams would qualify directly to the group stage and the other 32 would play in a preliminary phase, in the country where the World Cup is being played," Infantino told reporters at an event in Bogota, Colombia.
"They would play for the remaining 16 places. It means we continue with a normal World Cup for 32 teams, but 48 teams go to the party."
One of Infantino's proposals in his presidential manifesto was to increase the number of teams competing in World Cups to 40 after Qatar 2022.
A decision is set to be made on the plans at the FIFA Council Meeting in January 2017. The bidding process for the 2026 tournament had been due to take place next year, but has been put on hold amid allegations of corruption surrounding the 2018 and 2022 votes.
"These are ideas to find the best solution. We will debate them this month and we will decide everything by 2017," Infantino continued. "They are ideas which we put forward to see which one is the best.
"FIFA's idea is to develop football in the whole world, and the World Cup is the biggest event there is," he said. "It's more than a competition, it's a social event."
However, Infantino's expansion plans have been met with criticism and opposition from high-profile names in the sport.
