Retired football legend Ronaldo Luis Nazario de Lima, who is a member of Brazil's World Cup organising committee, has said that only 30 percent of the infrastructure projects undertaken for the tournament would be completed in time.
Brazil has promised a host of projects in conjunction with the World Cup to improve its roads, airports and urban transport networks.
But the country has struggled to finish even essential ones such as stadiums, and has shelved much of the rest.
"I think we're missing an opportunity. A series of investments were promised that won't be delivered. Only 30 percent will be delivered," Ronaldo told a forum organised by newspaper Folha de Sao Paulo.
He also elaborated on remarks last week in which he said he was "ashamed" of the delays in preparing for the tournament, which kicks off June 12.
"My shame is for the people, who were hoping for major investments, that's the great legacy of the Cup for us. They were expecting a lot and they're the ones most hurt by the situation," the AFP news agency quoted him as saying.
The former Real Madrid and Barcelona star also joked about Brazil's tense relationship with FIFA. The world football governing body has sharply criticised the host country's delays.
"I don't think FIFA are going to want to organise another Cup here. They are going to be traumatised," he said.
Ronaldo, who this week endorsed opposition senator Aecio Neves for presidential polls in October, voiced sympathy with protesters angry over the more than $11bn being spent on the tournament, but called for them to refrain from violence.
"Protests are always valid. But as soon as there are vandals taking part, people in masks, the security forces have to contain the offenders," he said.
Brazil was shaken by sometimes violent demonstrations that drew a million people into the streets last year during the Confederations Cup, a World Cup dress rehearsal.
New strikes and protests have erupted as the World Cup approaches, though they have been smaller than last year's.