LONDON (Reuters) - Olympic skeleton champion Lizzy Yarnold says she may boycott next year's world championships in the Russian resort of Sochi because she believes her sport is "not clean".

Britain's Yarnold won gold at the Sochi Olympics in 2014 -- a Games that has since been overshadowed by the findings of the McLaren report which outlined state-sponsored Russian doping.

She has called on the International Bobsleigh and Skeleton Federation (IBSF) to have "serious conversations" about whether Sochi should be hosting the championships.

"The IBSF need to have some serious conversations over the next few months and decide what they are going to do," Yarnold, back from a year's sabbatical, told the BBC.

"I'm not sure whether I want to compete in Sochi or can compete in Sochi if I don't know it's a clean playing field.

I'll leave it open. But I want the IBSF to make a decision that defends the true values of clean sport."

The McLaren report, published in July, revealed a Russian doping program that spanned the London 2012 Olympics and the 2014 Sochi Games. Evidence from former head of Russia's national anti-doping laboratory Grigory Rodchenkov claimed dozens of Russian athletes were doping at the Winter Games.

Another report is imminent.

"We've had these McLaren reports which have lots of allegations and I just hope that if people can be convicted of doping they should serve their time," Yarnold said.

"It's very important to me to compete in sport for the right reasons, to have sportsmanship and to be clean; to stand on the start line and to trust in the system -- and at the moment the system just isn't up to it."

(Reporting by Martyn Herman, editing by Pritha Sarkar)