Beleaguered world athletics boss Sebastian Coe admitted Monday there would be no quick fix as he battles to restore public trust in the crisis-hit sport.

But the 59-year-old Briton, on a visit to Japan in his capacity as chairman of the British Olympic Association (BOA), promised to "deliver a clean platform for clean athletes".

"I'm sure that the changes that I have in train will be, in large part, in place by end of this year," said Coe, whose first five months in charge of the sport's governing IAAF have been plagued by doping and corruption scandals.

"As I've said before, the journey back to trust is one of an uncertain length, but we have to make changes," he added.

"We have to push on with the reforms that I have been given the go-ahead with from our previous council meeting. I will report to our next council meeting in a few weeks time but, yes, those reforms are very, very important."

Since taking over from Senegalese Lamine Diack last August, Coe has faced criticism after Russia was banned after being found guilty of "state-sponsored" doping, while a slew of top IAAF officials -- including the disgraced Diack -- have been accused of accepting bribes from drug cheats.

Coe has denied a cover-up despite the conclusion of Dick Pound, chair of the World Anti-Doping Agency's independent commission, that he "could not have been unaware" of how widespread drug use was in athletics, having served eight years as vice president under Diack.

Coe, who won back-to-back Olympic 1,500 metres gold medals at the 1980 and 1984 Games, was ultimately endorsed by Pound as the right man to repair the sport's tarnished image.

- No ambiguity -                  

"We have to move the debate back to one of trust and integrity," said the former British member of parliament after signing an agreement for British athletes to use training facilities in Yokohama and Kawasaki at the 2020 Tokyo Olympics.

"One where the clean athletes know that there is no ambiguity at all in the federation about delivering a clean platform for clean athletes."

Coe also rejected the idea that British athletes could be tempted to stay away from this year's Rio Olympics as global health chiefs struggle to bring the mosquito-carried Zika virus under control.

"No, British athletes are not reluctant at all to compete in Rio," he said. "We have a proud tradition of having been at every Olympic Games since 1896, winter and summer, and all the British competitors are looking forward to it."

Alarm has spread over the virus since the World Health Organization (WHO) recently declared Zika an international emergency, prompting concern it could have an impact on the decision of athletes to compete, particularly if the situation worsens.

"The current issue is one that all national Olympic committees will be dealing with," said Coe. "We are speaking and working very, very closely with the organising committee and other agencies in Rio. But we are very much looking forward to being there."