In a rare interview given to international media, Nuzman conceded that delays had slowed the work down, with the final venue master plan having not been completed until last September, but he insisted everything would be ready. (Agencies)
"We know don't have time to lose and we are not standing still," Nuzman, who is also the head of the Brazilian Olympic Committee, told a Greek newspaper.
"Bringing the Games to Brazil was an ambition I held for a very long time and we are determined that we will deliver a Games to be proud of, within the agreed schedules and budgets,” he added.
Last month International Olympic Committee (IOC) vice president John Coates labelled Brazil's preparations the worst he had ever seen and critically behind schedule.
Attending an Olympic forum in Sydney, Coates told delegates construction had not started on some venues, infrastructure was significantly delayed and water quality was also a major concern two years out from the Games, although he later said he was certain the city would be able to host a "great" event.
Nuzman responded by saying that "working as a team is the best and only way to make this progress, but we need constructive criticism which can help us improve".
The first Games on the South American continent have been plagued by delays, rising costs and bad communication between different levels of the Brazilian government and organisers, prompting criticism from international sports federations.
The IOC announced a series of unprecedented measures in April to kick-start lagging preparations, including setting up a special task force, employing extra monitors and sending project managers and teams of experts.
Amid problems with stadium construction, labour unrest and security in other parts of the country, thousands of troops were deployed to Rio's slums in February to wrest them back from the control of drug gangs and criminals.
Turning to the finances behind the Games, Nuzman said the role of his organising committee should be distinguished from that of the three levels of government - the central administration and regional and municipal authorities.
"Transparency is a key theme in our project and we have worked very hard together with our government partners to deliver robust and transparent budgets," he said.
"It is important to draw the distinction between the Organising Committee budget, which comes entirely from private resources, and the government infrastructure, legacy and venue budgets which are for the long-term improvement of the city to benefit its residents and involve private and public money."
In January officials said the operating budget for the Olympics and Paralympics had jumped 27 percent from prior estimates to 7 billion real (USD 3.15 billion), citing factors such as inflation and costs for new technology.
In a rare interview given to international media, Nuzman conceded that delays had slowed the work down, with the final venue master plan having not been completed until last September, but he insisted everything would be ready.