The IOC co-ordination commission, led by former hurdles champion Nawal El Moutawakel, will wrap up its tour on Monday. It's the inspectors' fifth trip to Rio to check progress.
Several co-ordination commission members have been outspoken about forcing Rio organizers to speed up games preparations. During the last visit six months ago, IOC executive director Gilbert Felli said: "We don't have any yellow card to send to Rio."
A warning this time would be major embarrassment to local organizers and recall the 2004 Olympics in Athens when then IOC President Juan Antonio Samaranch issued a "yellow card" reprimand to Greek organizers.
The widely circulated Brazilian newspaper O Estado de S. Paulo, citing what it said were confidential IOC documents, said Saturday that phases of the Rio Olympics were at "serious risk" because of construction delays, a shortage of hotel rooms and a myriad of related problems.
The newspaper, which did not say how it obtained the documents, said only half the games projects were on schedule. It said the IOC rated progress into three categories — red light, yellow light and green light. It said the IOC listed infrastructure projects in the red category — meaning behind schedule.
Citing the document, the newspaper said the IOC was concerned about progress on a 16-kilometre (9-mile) subway-line extension into the Barra area — the centre of the games. It also said there were problems with a port redevelopment plan and plans to upgrade Rio's rundown airport.
Another problem area cited was the Deodoro Olympic Park, one of four core areas for the games. Plans to renovate this run-down northern part of the city are far behind schedule. The area will host equestrian events among others.
The paper said the IOC document showed Rio had lined up only 19,200 hotel rooms, when about 45,000 are required. It also said organizers were having problems lining up cruise ships to dock in the port area and provide extra hotel space.
The document also said that projects dealing with water supply and electricity had to be monitored.
In a statement to The Associated Press, the IOC acknowledged it produces various documents to monitor games progress. It said this was not unique to Rio.
"In a project of this size and complexity, it's standard for organizing committees to have different colours during the preparations and some may even remain red right up until the end of the preparation period ... although they will be delivered in accordance with what was planned."
This is a challenging moment for South America's largest country, which is trying to organize two mega-events and is facing pushback from citizens who question spending so much on sporting events, particularly in a country with vast inequality, high prices and a slowing economy.
Brazil is spending about $13.3 billion of largely public money on next year's World Cup. Olympic organizers are expected to announce their budgets in a few months, but public spending could be similar to that on the World Cup — or higher.
Leo Gryner, chief operating officer of the Rio games, acknowledged in a recent interview with The Associated Press that organizers got a "six to eight month" late start on building venues.
Gryner said that $700 million in public money may be needed to balance the operating budget. This is the budget to run the games themselves and is expected to be as much as $4 billion when it's announced. He said any shortfall was due to inflation, the sluggish economy and a struggle to sell local sponsorships.
Gryner said the capital budget — a mix of public and private money aimed at building supporting infrastructure for the Olympics — could be 35 per cent above the $11.6 billion listed in the original bid.
In addition to the pace of preparations, inspectors may have face questions about the following:
— WADA's suspension of an anti-doping laboratory in Rio. The lab — the only WADA-accredited facility in Brazil — can reapply for accreditation, but the revocation is an embarrassment to games officials.
— The resignation several weeks ago of Marcio Fortes, who headed the public body co-ordinating planning for the games among the local, state and national governments. Fortes, who handed in his resignation to Brazil President Dilma Rousseff, headed the Olympic Public Authority — APO — and complained he had been marginalized in decision making. Rio Mayor Eduardo Paes has said co-ordination is going well and the position is not needed.
— The readiness of the Maracana stadium and Joao Havelange stadium. Havelange is the venue for track and field and the Maracana will host football and the opening and closing ceremonies.
SNTV producer Filipe de Almeida contributed to this report.
Follow Stephen Wade at http://twitter.com/StephenWadeAP