(Reuters) - Venezuelan President Hugo Chavez said Sunday that his country would not recognize a ruling by a World Bank tribunal in a multibillion-dollar arbitration case with Exxon Mobil Corp (XOM.N).

Exxon took Venezuela to the World Bank's International Center for Settlement of Investment Disputes, or ICSID, seeking as much as $12 billion in compensation after Chavez ordered the nationalization of the Cerro Negro oil project in 2007.

I tell you: we will not recognize any decision, Chavez said during a televised speech. He has repeatedly accused the U.S. oil major of using unfair deals in the past to rob the South American OPEC member of its natural resources.

Last week another arbitration panel, of the International Chamber of Commerce, awarded the U.S. company $908 million in a separate case relating to the Cerro Negro nationalization, turning attention to the ongoing World Bank proceedings.

On Saturday, Venezuelan Oil Minister Rafael Ramirez told Reuters he did not expect a verdict in that case before the end of this year. It is due to start being argued in February.

Both cases have been closely watched by the industry for precedents in future disputes between companies and producing states, which have increasingly sought a greater share of oil revenue as prices soar and new reserves become tougher to find.

(Reporting by Daniel Wallis; Editing by Eric Beech)