A spokesman for the Alcohol and Gaming Commission of Ontario said Wednesday the event didn't qualify for a special occasion permit because it is not considered "of municipal significance," a designation that must be granted by city council.
"That's not our call," Jeff Keay said.
Last year's Ford Fest obtained the permit by applying through the caterer, Muzik Nightclub, which already had a liquor licence, Keay said.
Ford, who returned to city hall this month after seeking treatment for alcohol addiction, said organizers simply weren't able to get a permit in time for Friday's party.
"It was all timing, that's all it comes down to," he said.
"We're going to go ahead and invite everyone on Friday, July 25 to come out to Thomson Memorial Park and guarantee that people have a good time like they had the last 19 Ford Fests."
Guidelines posted on the commission's website say applications must be submitted at least 30 days in advance.
Keay said the application for Ford Fest was filed July 7, but added a permit could "theoretically" be granted by Friday should council deem the event to be of municipal significance.
The celebration was originally held at the family home but moved to public parks in recent years as it drew larger and larger crowds.
A spokeswoman for the city said organizers were issued a permit Tuesday allowing them to hold the event in the east-end park.
But Jackie DeSouza said the mayor's office has been warned there can be no campaigning at Ford Fest, since a city policy prohibits it in public parks.
Toronto voters go to the polls Oct. 27 and Ford has vowed to remain in the race, saying it would help his recovery to stay on as mayor.