International Olympic Committee president Thomas Bach on Sunday hailed the Sochi Games as "great", saying the response from the athletes was overwhelmingly positive.

He praised President Vladimir Putin for playing an "important role" in the Games and said the Russian strongman never committed any act that was not in line with the Olympic Charter during the Games.

"We are close to the end of a great Olympic Winter Games. The response we get from all the different participants is overwhelmingly positive," Bach added at a news conference ahead of the closing ceremony later Sunday.

"There was not a single complaint from any of the athletes," added Bach who spent several nights in the Olympic Villages.

"These were excellent Games that may lead to the reversal of some criticism" of the Russian organizers that preceded the Olympics, he added.

There had been huge alarm ahead of the Games not just about the ability of Russia to build the facilities on time but also its rights record and in particular the now notorious anti-gay law.

But Bach said: "Mr Putin always respected the Olympic Charter during these Games. I don't remember any action during these Games by him when he stepped over the border" for behaviour marked out by the Olympic Charter.

Bach said he would not use an adjective to sum up the success of the Games at his closing ceremony speech, as had been the tradition for some previous IOC presidents.

"Most likely what I want to do is not give my judgement but convey the message I heard from the athletes," he said.

He said athletes were particularly impressed by the proximity of their accommodation to their venues, meaning they could hop from breakfast tables to training in a couple of minutes.

Bach hailed the transformation of Sochi, recalling its "terrible" state when he was chairman of the evaluation commission for Sochi in 1994 for its second unsuccessful bid to host the Games.

"I came here and I said 'impossible'," recalled Bach.

"We saw an old Stalin-style sanatorium city where we were looking at the roof and wondering if you might get hit by something falling down."

"It was terrible. Seeing 20 years after this transformation is really amazing."

He said the priority for Sochi was securing the legacy after the Russian organizers made clear their ambition for the Games to transform the whole southern Russia region. (AFP)