Cafes and restaurant owners on London Road have criticised the closure of several entrances to the Green, which they say means spectators can't access their facilities.
Hundreds of thousands of pounds were spent regenerating the city's historic Calton area, including major improvements to market stalls, and shops were given money to makeover their premises ahead of the Games.
Shopowners now feel cheated, they say, unable to share the benefit of the huge influx of visitors.
Colin McArthur, who has run Mimi's cafe in London Road for three years, described the situation as "a shambles".
He said: "They've closed every entrance except the Saltmarket and the one at the other end of the park.
"We had six customers in here on the morning of the marathon.
"Two of them were going to the rugby and the others were just passing through. We are right opposite the main gate at Greendyke Street and it's all fenced off."
Mr McArthur said they had been told the gates were closed for "secondary security".
He said: "It's apparently to keep people inside safe from terrorist attacks.
He said Games officials were also directing spectators to walk on the other side of the street.
He added: "They are telling them to cross over, but there's nothing on the other side.
"It's as if they are going out of their way to keep people away."
Angela Singh, who runs nearby Spicy Fusion, said they were all suffering.
She said: "We got a grant to do the shops up and make ourselves look pretty for the Games.
"They said that, being on the edge of the Green, it was a chance for us to make some money.
"Then they changed the rules and started shutting the gates. People can't get out.
"This is not bringing people into London Road. Why did they spend so much money doing the area up?
"They promised us the Games were for the people of Glasgow but they are giving the money to official Games traders, leaving us high and dry."
A spokeswoman for Glasgow City Council said they "remained confident" that the influx of visitors "will be of huge benefit to local businesses".
He said: "On Sunday alone we saw more than 50,000 people visit the Glasgow Green Live Zone, with many local businesses benefiting from the increased footfall."