Would-be Olympics chief Ng Ser Miang said on Monday he was heartened by Russia's promise not to discriminate against homosexuals at next year's Winter Games, adding the event would be "wonderful".
The Singaporean supermarket chief, one of six men vying to replace International Olympic Committee (IOC) president Jacques Rogge, also played down other problems including Sochi's huge cost and a ban on protests during the event.
"Sochi has put in quite heavy investment because of the need for them to develop a lot of infrastructure," Ng told AFP in an interview at his office in Singapore.
"This anti-gay law, we now have a written assurance from the highest authority that there will be no discrimination of any kind, respect to the provisions of the Olympic Charter as well as the fundamental principle against discrimination of any kind.
"So the rights of those who are attending the Games, from spectators, to officials, to media, especially the athletes, will be respected.
"I believe that Sochi will be a wonderful Games."
The new Russian law banning "gay propaganda" has attracted widespread criticism and it was one of the main talking points at this month's world athletics championships in Moscow.
Russian pole-vault champion Yelena Isinbayeva caused uproar when she appeared to criticise homosexuals, although she later said she had been misunderstood.
Ng, a diplomat and former politician who is also a vice-president of the IOC, said the Olympics body stood firm against discrimination but also that he preferred a softly-softly approach.
"In some of these issues I believe in quiet diplomacy to deal with these issues," he said. "It's a common goal that we want to have a successful Games and the IOC is very clear and very strong -- the IOC is against discrimination of any kind."
One estimate has put the cost of Sochi's Games at $US50 billion ($A55.64 billion), which would make it the most expensive Olympics in history.
Russian President Vladimir Putin has courted more controversy by banning protests and demonstrations and restricting access to the Black Sea resort during the Games early next year.
Ng also backed Brazil's Rio de Janeiro, host of the next Summer Olympics in 2016 as well as next year's World Cup, to have the infrastructure in place to host a successful Games.
"Rio has put in a lot of resources. Definitely they have a lot of challenges because they're hosting the World Cup before the Games themselves," he said.
"But they are fully aware of the issues and they are fully aware of the challenges and they're also aware of the very tight timeframe they are in.
"I'm sure they'll put in all the necessary resources to make sure that we have a wonderful Games. The IOC is fully behind Rio and we will give our fullest support to them and do everything in our power to make sure they will organise a wonderful Games."
Ng, considered a strong candidate behind front-runner Thomas Bach, will soon travel to Buenos Aires, where the IOC will elect its new leader on September 10.