ISTANBUL—Iraq's council of ministers has approved a deal valued at more than $15 billion with the U.K's BP PLC and Hong Kong's CNPC to develop Rumaila, Iraq's largest producing oil field, a top oil official said Saturday.

"The cabinet unanimously approved the Rumaila contract with BP and CNPC during a special session held late Friday night," Sabah al-Saadi, head of the legal department at the oil ministry's Petroleum Contracts and Licensing Directorate said at an oil conference in Istanbul.

Mr. Saadi said both sides were expected to sign the deal "within a few days" at the ministry's offices in Baghdad.

Toby Odone, a London-based spokesman for BP, said the Iraq government hasn't officially notified the company about the cabinet's approval. "If that has happened, it is great," he said.

Senior officials from Iraq's oil ministry will brief representatives from 45 international oil companies on Sunday about new oil and gas fields open for auction in December.