BP originally expected the payout programme to cost $7.8 billion (5 billion pounds), but it has said the final bill, from the uncapped agreement that is handling thousands of claims, could be considerably higher.

The oil major has filed numerous motions to challenge what it says are excessive fees charged by the programme's administrator, generous payments made under disputed accounting rules, and phony claims.

U.S. District Court Judge Carl Barbier in New Orleans has thrown out many of those complaints and turned the company down again on Wednesday.

The oil company has sustained more than $42 billion in charges from the April 20, 2010 disaster aboard the Deepwater Horizon drilling rig that killed 11 workers and triggered the worst offshore oil spill in U.S. history.

Earlier this month, Barbier found the company "grossly negligent" for the spill, a finding that could greatly increase its fines under the federal Clean Water Act at the next phase of the ongoing civil trial in January, when penalties will be assigned.

(Reporting by Terry Wade; Editing by Bernadette Baum)