June 4 (Bloomberg) -- Total SA said a planned 400,000 barrel-a-day refinery in Jubail, Saudi Arabia, to be built with the country's state oil company Saudi Aramco, will cost almost $12 billion, more than previously forecast.

Chief Executive Officer Christophe de Margerie told a commission at the French National Assembly in Paris today that the investment would be ``close to $12 billion,'' higher than an estimate of ``more than $10 billion'' given last month.

``There is no official figure for the simple reason that it doesn't yet exist,'' de Margerie told journalists after a speaking to the deputies.

The company, based in Paris, is starting the tender process for construction of the plant, he said. The companies announced last month a joint venture for the refinery in which Saudi Aramco will own 62.5 percent and Total the remaining 37.5 percent. Construction contracts will be awarded by the first quarter of 2009.

``Costs are spiralling upward,'' he said, reiterating that he doesn't want to ``send a message to contractors'' by giving an estimate that may send prices even higher.

He estimated at the company's annual shareholders' meeting on May 16 that the plant would cost more than $10 billion, up from an earlier forecast of $6 billion.

The planned refinery will sell most of its output in Asia, Arab Oil & Gas reported on May 30, citing Total Vice President Jean-Jacques Mosconi.

To contact the reporter on this story: Tara Patel in Paris at tpatel2@bloomberg.net

Last Updated: June 4, 2008 11:49 EDT