(Adds Lawson quote, details, background)

LAGOS/ACCRA, Oct 30 (Reuters) - Pan-African lender Ecobank (ETI) EBG.GH ETI.LG said on Wednesday its chairman Kolapo Lawson will stand down with immediate effect, in a bid to restore confidence in a bank rocked by governance issues.

Ecobank has seen its image take a hit from allegations by suspended head of finance Laurence do Rego that she was asked to misstate 2012 results and that assets were being unnecessarily sold at a loss. ID:nL6N0GV2F0

Nigeria's security and exchange commission is investigating the allegations, which Ecobank denies, although its chief executive has said transparency could be improved.

The African lender first came into the spotlight in April when Nigeria's central bank notified it of Lawson's failure to repay 1.4 billion naira in debts sold to AMCON, the state-owned "bad bank", and a further 1.6 billion naira owed to Ecobank by businesses associated with him.

Ecobank has since said Lawson has repaid the debts owed to it and no company rules were broken. ID:nL6N0G14JQ

AMCON declined to comment on the basis of confidentiality.

Banking analysts have highlighted that these loans only account for 0.1 percent of ETI's total loan book. ETI shares are up 22 percent so far this year and closed at 13.80 on Tuesday. Nigerian markets open at 0930 GMT.

Lawson said on Wednesday that independent parties would investigate allegations and review corporate governance.

"I decided that it wasn't appropriate for me to preside over the (review) process so I thought it was best to step aside. It's something I've been thinking about for a long time," Lawson told Reuters by telephone.

(Reporting by Chijioke Ohuocha in Lagos and Matthew Mpoke Bigg in Accra; Writing by Joe Brock; Editing by David Cowell and David Holmes)

((joe.brock@thomsonreuters.com)(+234 803 400 4222)(Reuters Messaging: joe.brock.thomsonreuters@reuters.net))

Keywords: ECOBANK CHAIRMAN/