Coe was speaking after International Olympic Committee vice-president John Coates in April criticised the Rio preparations as "the worst that I've experienced" in 40 years of being involved with the Olympics.
Coates later backtracked on his comments, saying he believed Rio could still deliver "an excellent Games" but that "time is of the essence".
Coe, the former head of The London Organising Committee of the Olympic and Paralympic Games, told AFP: "This is hard. I know this. No city is ever challenged in the way that it is when you deliver a Games, and I know that from experience.
"The Rio Games will be fine. The question we should be asking is what can the world of sport do to help when it is needed and I think there is a great will for the Games to go well in Brazil.
"The organising committee is a good organising committee and I am sure the Games will be successful."
The current chairman of The British Olympic Association was speaking on the sidelines of the Diamond League athletics meeting in Shanghai.
The Rio Games' organisers were forced to issue a statement following Coates' scathing criticism that they would deliver their "historic mission" with IOC support.
Despite this, worrying signs remain.
Work at the Olympic site in Rio's Deodoro district was due to start last year but was now expected to start in September. And a recent strike by workers at the Barra da Tijuca district in western Rio, which will host a slew of events, also caused delays.
Beyond construction issues, the city must also work on cleansing sewage-contaminated water in Guanabara Bay, which is due to host sailing and windsurfing vents.
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