Kenya, Russia and Mexico will come under further scrutiny from the International Olympic Committee (IOC) ahead of Rio 2016 to ensure they meet doping regulations.
The IOC executive board gave its full support to fight against doping on Wednesday, doubling their budget ahead of the Games in Brazil and paying special attention to certain countries who are non-compliant with doping rules.
Athletes from 12 different countries were found to have failed doping tests during the 2008 Games in Beijing when their samples were retested, with the IOC threatening bans for the upcoming Olympics.
Samples from London 2012 will also be re-examined as the IOC look to keep the Games clean, with a medallists from the previous two Olympics targeted for re-analysis.
To aid this fight the governing body have vowed to up the resources around the programme, while a Disciplinary Commission has been set up to deal with implicated athletes ahead of the start of the Olympics in August.
"The fight against doping is a top priority for the IOC, which has established a zero-tolerance policy," a statement read.
"Today, we are taking further decisive action to protect the clean athletes at the Olympic Games Rio 2016.
"The IOC will not hesitate to punish anyone within its reach responsible for using or providing doping products or methods, including officials, coaches and other members of the athlete's entourage."