KABUL (Reuters) - Afghan President Ashraf Ghani's nominee for agriculture minister in his new Cabinet is on an Interpol wanted list for tax evasion in Estonia, a fact Ghani's spokesman said was unknown to his office at the time of his nomination.

Interpol's website lists Mohammad Yaqub Haidari, 52, as wanted in Estonia for "large-scale tax evasion, fraudulent conversion" in cases dating back to 2003.

A spokesman for Ghani, Nazifullah Salarzai, said on Saturday the presidential office was unaware Haidari had any legal troubles but was investigating.

Although Haidari has been on the wanted list for years, it was not widely known or reported in Afghanistan.

Ghani, who was sworn in as president last year to replace long-time leader Hamid Karzai, has vowed to root out widespread corruption and said he would choose his ministers based on their qualifications, not their connections.

Afghanistan was ranked as the world's fourth most corrupt country last year by the watchdog Transparency International. It has topped the list in previous years.

Ghani's Cabinet nominations were announced on Monday, after a wait of more than three months over negotiations with unity government partner Abdullah Abdullah, his former election rival. [ID:nL3N0UR34C]

Haidari confirmed on Saturday that he is on the Interpol wanted list but insisted he is innocent.

"I am being targeted by a political conspiracy. When you enter the world of business and politics, this is what happens," he told Reuters.

He said the taxes were owed not by him but by a person who bought a company from him that did business in Estonia.

A biography of Haidari compiled by the Afghanistan Analysts Network cited a recent television interview in which he said he once ran an agricultural import-export company that did business in eastern Europe and Russia.

His current business is focused on construction and information technology, as well as agricultural products, the profile said.

(Editing by Raissa Kasolowsky and Paul Tait)