International Olympic Committee (IOC) vice president John Coates called Brazil's preparations for the 2016 Rio de Janeiro Games "the worst" he has ever seen and critically behind schedule, but warned there is no "plan B" to find another host.
Attending an Olympic forum in Sydney, Coates told delegates that construction has not commenced on some venues, infrastructure is significantly delayed and water quality is also a major concern two years out from the Games.
"I think this is a worse situation than Athens," said the Australian, referring to preparations for the 2004 Games, which were plagued by construction delays.
"In Athens, we were dealing with one government and some city responsibilities. Here, there's three.
"There is little co-ordination between the federal, the state government and the city - which is responsible for a lot of the construction.
"And this is against a city that's got social issues that also have to be addressed; a country that's also trying to deal with the FIFA World Cup coming up in a few months.
"It's the worst that I've experienced."
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 measures earlier this month to kick-start lagging preparations, including employing extra monitors and sending project managers and teams of experts.
"The IOC has formed a special task force to try and speed up preparations but the situation is critical on the ground," Coates said earlier in a statement released by the Australian Olympic Commission.
"The IOC has adopted a more hands-on role, it is unprecedented for the IOC but there is no plan B. We are going to Rio.
"We have become very concerned, they are not ready in many, many ways. We have to make it happen and that is the IOC approach, you can’t walk away from this."
CAN'T WALK AWAY
Brazil has been under the spotlight for the more immediate concern of the soccer World Cup finals starting in June.
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.
Coates has made six visits to Rio as a member of the IOC's coordination commission.
Although Rio organisers boasted the same number of staff as London's two years before the 2012 Games, they lacked experience, Coates said.
He pointed to only two staff working in the Games' tests department, though test events were scheduled to start this year.
As Australian Olympic Committee president, Coates also spoke of the country's sports leaders and team managers "not getting answers" to any of their questions on visits.
"Can they use the carparks in the village for recovery centres? What will be the time to take from this venue to this venue?
"All of those things, they're being fobbed off.
"But again, we just have to make it happen - and that's the IOC's approach. You can't walk away from this.
"If it comes off - the first Games on the South American continent, in a magical city in so many ways - it'll be a wonderful experience for the athletes."
Image: Construction workers on strike stand outside the Rio 2016 Olympic Park construction site in Rio de Janeiro.
Photograph: Ricardo Moraes/Reuters