Infantino's proposal for a 48-team World Cup in 2026 will be submitted to the FIFA Council next month.
"I strongly believe in that, but obviously I'm not a dictator," Infantino told the closing session of the Dubai International Sports Conference.
"This is something that needs to be discussed. When discussed with the associations in the summits they were overwhelmingly in favour, but more discussions will have to take place," he said.
Infantino's proposal for a 48-team World Cup in 2026, featuring 16 groups of three, will be submitted to the FIFA Council next month. A 40-team World Cup is also on the table.
Infantino said that expansion means "inclusion" in the "biggest social and sporting event."
He said failure to qualify for the finals strongly affects nations, with coaches being sacked and clubs and players criticised.
If they qualify "the whole country lives and breathes football. Everyone gets interested," he added.
The European Club Association, the powerful body representing Europe's top clubs, told Infantino earlier this month that it opposes a bigger World Cup, saying leading players were already under too much strain.