Global stem cell experts say the verification of cloning pioneer Hwang Woo-suk's thesis by an independent body overseas is inevitable to end suspicion over his research's validity.

The creator of the world's first cloned sheep, Ian Wilmut, and seven other renowned scientists on Thursday said in media interviews that the controversy will likely not end soon and ruled out technology leaks in the verification process.

Wilmut said he also referred his work to a third agency after an allegation surfaced that his cloned sheep was a fake.