Usain Bolt is reconsidering his plan to retire from athletics after the 2016 Olympic Games in Rio de Janeiro. The 27-year-old had suggested he would quit in 2016, but he now admits it is probable that he will compete for another year after that.

Bolt, who won 100m, 200m and 4x100m gold at the last two Games, also said he has informed his coach that he wants to run at the 2014 Commonwealth Games, which are taking place in Glasgow. "I am definitely reconsidering [retiring after 2016]. I think my fans have voiced their concern about me retiring," he said. "They think I should carry on and so do my sponsors. I have discussed it with my coach and he says it is possible. We will see what happens but it's on the cards that I will extend it by one more year."

One of the few medals Bolt is yet to add to his collection is Commonwealth gold, having never competed at the event. In 2006 he was due to go to Melbourne but pulled out because of a hamstring injury and then opted out of New Delhi in 2010. "I have said to my coach that I would love to go to the Commonwealths," Bolt said. "It's something that I haven't done before. It's up to him but I have said to him that I want to be a part of it. My coach will think about it and we will see what he says. I am not 100% sure. We will discuss and see what he says." He told the BBC he would probably run only the 200m.

Usain Bolt will be hoping to repeat his London 100m gold medal celebration in Rio de Janeiro. Photograph: Michael Steele/Getty Images

Bolt, who claimed three golds at the world championships in Moscow this summer has welcomed the news that Jamaica will step up their drug-testing regime after five of the island's athletes tested positive for banned substances this year, including the former 100m world record holder Asafa Powell.

Jamaica's prime minister Portia Simpson-Miller has promised the World Anti-Doping Agency that testing remains a priority and Bolt said: "Anything that helps Jamaica to prove to the world that we are clean and that we are the best, I welcome fully. She says she is going to implement these things to make the sport better so it's a joy for me."

He would become the oldest 100m champion of all-time if he won gold at Japan in 2020, when he will be on the verge of turning 34, but he insists he has no desire to extend his career that far. "I have not thought about [Japan]," Bolt added. "It's a long way away, but if I win the next Olympics I will have done everything I wanted to do in my career so there would be no reason to continue."