Rio's preparations for the 2016 Summer Olympics came under fire from International Olympic Committee (IOC) members for the first time in public in Buenos Aires on Sunday.

Brazilian IOC member Carlos Nuzman was put under pressure after presenting an update on Rio's progress where he insisted they would be ready on time but that a lot of work still lay ahead.

IOC Coordination Commission chief Nawal El Moutawakel admitted that while progress had been made there was room for improvement.

The 51-year-old Moroccan, the inaugural winner of the women's Olympic 400m hurdles title in 1984, said the organisers should learn lessons from the protests that took place during Brazil's hosting of the Confederations Cup earlier this year.

Hundreds of thousands demonstrators turned out over weeks to protest higher mass transit fares and call for better public services, including transportation, and complained about the vast investment being made in the World Cup next year and the Olympics.

"Over recent months, the social and political environment and operations have significantly changed," said El Moutawakel, who visited Rio with her fellow members of the Commission last week.

"There is a need, more than ever before, that all stakeholders need to work together.

"Key decisions need to be made collectively and communicated with one voice."

El Moutawakel, a former sports minister in Morocco, said that she still felt Rio could put together a great Games.

"We remain confident Rio and Brazil have the resources and the energy and ambition to deliver a memorable Olympic Games in 2016."

Veteran Australian IOC member and head of the Press Commission Kevan Gosper was not so guarded and, admitting it was not easy as Nuzman was a 'friend of his', warned his colleague things needed to improve quickly in terms of getting their message across to the people of Rio.

"I'm still concerned with the delay related to your press operations. It took you three-and-a-half years to appoint a media chief," said the 79-year-old, who won a silver medal in the 4x400 metres relay at the 1956 Olympics in Melbourne.

"You simply have to keep your public aware about what's happening.

"If the community doesn't get it, you'll have a repeat of what you've had (protests)."

Their concerns echoed those of some other IOC members who said that they had voted for Tokyo ahead of Istanbul to host the 2020 Games on Saturday because of the slow progress being made by Rio and did not want to have to endure the possibility of a repeat of that for the following edition.