The retired player said the Australians had paid the price for a heavy three-week training program organised by Buchanan with a view to being at full fitness for next month's World Cup, but left the team flat in the finals.
''From what I hear, the boys trained really, really hard -- probably too hard -- and it affected them,'' Warne said yesterday to the Herald Sun.
''They got tired for the finals and didn't perform really well, so John Buchanan has to take responsibility for that,'' the blonde spinner said.
Warne, who has not always agreed with Buchanan's methods, said the wrong plan had again been adopted.
''If you're playing international cricket, all you want to be is fresh and happy,'' Warne said.
''You don't want to be trained into the ground. But that's the way he wanted to do it, but it didn't work out. Hopefully, it will hold them in good stead for the World Cup,'' he added.
There has already been some fallout to the grueling program, which featured sessions lasting up to four hours with the most notable one being Andrew Symonds.
Buchanan yesterday admitted the workload had been a factor in the loss.
''Factors that had some bearing on the overall results were our continuing to maintain a high workload through competition, World Cup selections and strategies. Trying to play a competition, but with other end points in mind, and player loss to and return from injuries,'' Buchanan said.
Warne's thoughts were echoed by Cricket Australia board member Allan Border, who expressed reservations about the heavy workload.