"We are now able to confirm a cover up that dates back until at least 2011 and continued after the Sochi Olympic Games. It was a cover up that evolved from uncontrolled chaos to an institutionalised and disciplined medal-winning conspiracy," McLaren told a news conference on Friday.
"It was a cover up an unprecedented scale and the second part of this report shows the evidence that increases the number of athletes involved as well as the scope of the conspiracy and cover-up.
"We have evidence revealing that more than 500 positive results were reported as negative, including well-known and elite-level athletes, who had their positive results automatically falsified."
McLaren said Russia won 24 gold, 26 silver and 32 bronze medals at London 2012 and no Russian athlete tested positive.
"Yet the Russian team corrupted the London Games on an unprecedented scale, the extent of which will probably never be fully established," he said.
"The desire to win medals superseded their collective moral and ethical compass and Olympic values of fair play.
"For years international sports competitions have unknowingly been hijacked by the Russians. Coaches and athletes have been playing on an uneven field. Sports fans and spectators have been deceived and it is time that this stops."
The report said a urine sample swapping technique used at Sochi became regular practice at the Moscow laboratory that dealt with elite athletes.
It added that four Sochi gold medallists had samples with physiologically impossible salt readings, while 12 Russian Sochi medallists had evidence of tampering with the bottles containing their urine samples.
The original McLaren report, released in July, was one of two commissioned by WADA which revealed widespread state-sponsored doping in Russian sport.
The July report found Moscow had concealed hundreds of positive doping tests in many sports ahead of the Sochi Games and led to a partial ban of Russian athletes competing in Rio de Janeiro Olympics in August.
Although Russian track and field athletes and weightlifters were banned from competing at Rio, the International Olympic Committee rejected a blanket ban and let international sports federations decide which athletes should be eligible to compete.
The evidence contained in the report can be found at the website: