Preparations for the Rio 2016 Olympic Games are the "worst ever seen", according to International Olympic Committee (IOC) vice president John Coates.

Coates, who has been involved with the Olympic movement for 40 years, said the IOC was taking the issue seriously and has already taken action by placing experts in the Brazilian organising committee to make sure the Games can go ahead.

Speaking at an Olympic forum in Sydney, Australia, he added that progress on the Games infrastructure and venues with two years to go was worse than it was for the Athens Games in 2004.

While Athens was notorious for delays in construction, all venues were completed just in time for the Games.

In Rio, building work hasn't even started on some of the venues, despite the first test events being scheduled for later this year.

The opening ceremony for Rio 2016 is due to take place on 5 August at the iconic Maracana Stadium. The venue, one of the few that are already completed, will also play centre stage at this year's FIFA World Cup.