"I'm not really happy with the situation and with how it was done," Bolt told Reuters on Tuesday.
"I think for someone like Asafa (Powell) to get a ban of 18 months for that (stimulant oxilofrine) and then Tyson Gay get just one year because of cooperating, I think it is sending a bad message into the sport that you can do it (dope) but if you cooperate with us, we'll reduce the sentence," the 100m and 200m world record holder and six times Olympic gold medallist said.
The sanction, handed to Gay by the United States Anti-Doping Agency (USADA), ended in June this year.
Gay, who returned to competition on July 3 and ran 9.93 in the 100 metres at the Lausanne Diamond League meeting, is the world's joint second fastest man along with Yohan Blake (9.69).
Both the World Anti-Doping Agency (WADA) and track and field's world governing body, the IAAF, have accepted the controversial ban.
"I don't think that's the right way to go because you are pretty much telling people that this is a way out, it's a way of beating the system, so personally, I don't think the IAAF dealt with that very well," Bolt said.
WADA told Reuters in early June that it was satisfied with the decision, while later that month, the IAAF said that it would not appeal Gay's ban.
"After careful review of the full file provided by USADA, the IAAF has decided that the one-year sanction applied in the case of Tyson Gay was appropriate under the circumstances and in accordance with IAAF Rules," it said in a statement to Reuters.
Athletes normally receive two-year bans for their first major doping offence, but under anti-doping rules the sanction can be reduced for substantial cooperation.
USADA had said Gay was eligible for such a reduction because he offered what it termed "substantial assistance" in his case.
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