US construction firm Bechtel is set to be awarded an additional $350m (£222m) of work in Iraq, according to a report in the Wall Street Journal.
The paper said the move was part of plans by the US government to accelerate the rebuilding of Iraq's economy.
In April this year Bechtel won a contract worth up to $680m covering repair work on power generation facilities, the electricity supply, and water and sewage systems.
A spokesman for Bechtel told BBC News Online that the company had not been notified of any extension to their contract.
He added that it was entirely up to the US Agency for International Development (USAID) and the Coalition Provisional Authority (CPA) as to how they wanted to proceed.
The initial $680m contract over 18 months was the largest of the reconstruction contracts handed out by USAID earlier this year.
But the Wall Street Journal said US officials and Bechtel assessment teams now reckon that amount will cover less than 4% of the total sum needed.
The paper said the contract extension is part of more than $1bn that the US government wants to put into Iraq's power industry over the next year.
It added that the push for new funds showed how much the government underestimated the cost of rebuilding Iraq.