Former World Anti-Doping Agency (WADA) chief Dick Pound warned on Wednesday that Russia's international ban may still be in force at the Rio Olympic Games.
Russian athletes were banned from competing internationally last year after an independent commission chaired by Pound found evidence of state-sponsored doping in the country.
The Canadian told the Tackling Doping in Sport Conference in London that there remained a "wall of denial" about the extent of doping in Russian sport.
"The Russians seem to assume the controversy will disappear and there should be no question of their participation (in the Olympics) in Rio," he said.
Instead of concentrating on the reforms needed in order to return to the athletics fold in time for this year's Games, Pound said Russia was "rearranging deckchairs on the Titanic".
He added: "My guess is that Russia may not make it back for Rio. The IAAF (International Association of Athletics Federations) and WADA are not going to risk their reputations by rolling over and playing dead."
Speaking at the same event, WADA president Craig Reedie said the agency is prepared to extend its investigation into doping in Russian athletics to other sports in the country.
United States-based Russian tennis superstar Maria Sharapova is facing a ban after testing positive for the banned drug Meldonium and Reedie said that WADA would not hesitate to probe doping allegations in other sports.
"If evidence comes to light as part of the independent testing programme under way in Russia and our discussions with RUSADA (the Russian Anti-doping Agency) and if those discussions warrant further investigation, then we will take action," Reedie said.
Reflecting on a year that also saw football's governing body FIFA plunged into a corruption scandal, Reedie said: "The public's confidence in sport was shattered in 2015 like never before.
"The public mood has soured, cynicism has prevailed and there's a general feeling that they're all at it."
Reedie called for more investment in anti-doping programmes by sport's governing bodies, saying he was "perplexed the sports movement is reluctant to provide the investment required".