DUBAI (Reuters) - Sadara Chemical Co, a joint venture between Saudi Aramco and Dow Chemical (>> The Dow Chemical Company), has signed a fundraising package for the $19.3 billion (12.2 billion pounds) petrochemical complex it is building in the east of the kingdom, three banking sources said on Sunday.

The financing package totals around $12.5 billion and consists of loans from banks, export credit agencies and the state-owned Public Investment Fund, as well as proceeds from an Islamic bond issue. The remaining cost will be met by the two partners.

The facility, located at Jubail Industrial City in Saudi Arabia's Eastern Province, will be the world's largest chemical complex ever built in a single phase. It will produce more than 3 million tonnes of petrochemicals each year when completed in 2016.

Sadara was not immediately available for comment. The sources spoke on condition of anonymity as the matter has not been made public.

The split between the different portions of the facility were changed from an original outline released in May 2012 after the success of the sukuk, which was completed at the start of April, two of the bankers said.

Sadara raised 7.5 billion riyals (1.2 billion pounds) from the local currency Islamic bond, having increased the deal size from 5.25 billion riyals on strong demand from investors.

Also included is a $4.975 billion direct loan from the U.S. Export-Import Bank. Signed in September, it was the largest ever loan from the institution.

(Additional Reporting by Reem Shamseddine in Khobar, Saudi Arabia; editing by Jason Neely)

By David French