Governing body the FIA has already given Andretti’s bid to become F1’s 11th team its blessing, but the matter has now been passed on to FOM for final approval.
F1 and the existing teams’ current stance on the prospect of Andretti joining the grid has been lukewarm at best.
"Saying no to a team which has been approved by the FIA, it’s very hard to say no," Ben Sulayem told Reuters.
"The FIA should be asking, begging, OEMs to come in. We should not just say no to them.
"If you say: 'What is my dream?' It is to fill up the 12 [team slots] and to have one US team from an OEM and a [power unit] and a driver from there. And then go to China maybe and ask for the same thing and do it.”
Ben Sulayem rejected suggestions that it would be better for Andretti-Cadillac to buy an existing team, something Mercedes boss Toto Wolff had previously said.
"You cannot force Andretti/GM to buy another team just because [the current owners may] want to sell,” he said.
"I won't mention names, but they were after me to go on and convince GM to do that. It's not my job. I was not elected to do that. I am not a broker.”
According to Ben Sulayem, F1 should have more teams and fewer races.
"We are allowed to have 12 teams [in the rules]. Some of the teams said 'Oh, it will be crowded'. Really? We are already running a Hollywood team with us," he said in reference to the Brad Pitt F1 movie which has been filmed at some races this season.
"The circuits are supposed to have enough garages and space for 12 teams. I think the number of races is too much [rather] than the number of teams. We need more teams and fewer races.
"The teams are looking at the piece of cake. I understand their worries… but our worries are different.”
Ben Sulayem also moved to dismiss the notion of a power struggle between F1 and the FIA.
"We are not a service provider," he added. "We own the championship. We leased it - we are the landlord. So that has to be respected also.
"My intention was never to embarrass or to put someone in a corner, [F1 owners] Liberty or FOM [Formula 1 Management]. I am here for the spirit of the sport."