Nigeria head had no right to revoke oil block - KNOC

ABUJA, May 27 (Reuters) - Nigerian President Umaru Yar'Adua did not have the authority to revoke an offshore oil exploration licence from South Korea's National Oil Corp (KNOC) earlier this year, the oil firm's lawyers said in federal court on Wednesday.

Yar'Adua in January withdrew KNOC's rights to two oil blocks, initially awarded by the previous administration four years ago, because he said the company failed to fully pay the invesment pledged. KNOC denies this, saying it met its obligations.

Robert Clark, one of KNOC's lawyers, said that under Nigerian law only the minister of petroleum has the power to revoke the oil exploration licence.

"The president of the Federal Republic of Nigeria is not at the same time the Minister of Petroleum Resources," he said in a federal court in Nigeria's capital Abuja.

Yar'Adua revoked KNOC's oil licence on January 6, nearly a month after he appointed Rilwanu Lukman as minister of petroleum. Previous to this, Yar'Adua was both president and oil minister.

The next hearing is scheduled for June 10.

Former President Olusegun Obasanjo's administration in 2005 awarded a South Korean consortium led by KNOC rights to two key oil blocks, in return for a pledge of major infrastructure investment in Africa's top oil producer.

Preliminary estimates suggest that the revoked oil fields could hold as much as 1 billion barrels of hydrocarbons.

The consortium, which includes Daewoo Shipbuilding (042660.KS: Quote, Profile, Research) and Korea Electric Power Corp (015760.KS: Quote, Profile, Research), filed the suit to restore the licences in March.