Iraq will protect foreign firms against threats from trade unions seeking to block a major oil deal with BP and China National Petroleum Corporation (CNPC), a pillar of Iraq's bid to renew its struggling oil sector, an official said.

"The Oil Ministry stresses its rejection of threats and provocation toward anyone: the government, the ministry, foreign firms," Oil Ministry spokesman Asim Jihad said on Friday. "The government will protect the companies," he added.

Jihad said promises of strikes or sit-ins, designed to halt the deal with the BP and partner CNPC, were politically motivated and might be linked to posturing ahead of Iraq's national elections early next year.

The Federation of Oil Unions of Iraq and the Federation of Workers Councils and Unions in Iraq vow to mobilise workers against the government's plans to award the foreign group the right to develop Rumaila, Iraq's largest producing oilfield.

The 20-year deal was the sole contract awarded in Oil minister Hussain Al Shahristani's June 30 auction.

Abdullah Eskander Habib, a member of parliament's oil and gas committee, said such threats could make firms, already hesitant about setting up shop in a country just emerging from over six years of war, think again.