BlueScope Steel will raise $US300 million ($A289.70 million) to help pay off debt by issuing senior unsecured notes to institutional investors.

BlueScope on Friday said the notes would be offered by its subsidiaries BlueScope Steel (Finance) Ltd and BlueScope Steel Finance (USA) LLC.

BlueScope said the notes would be offered to institutional investors in the United States and elsewhere.

“If successful, BlueScope Steel will apply the net proceeds to repay existing indebtedness,” the company said.

“The notes issue will diversify BlueScope Steel’s funding sources and extend its debt maturities.”

In a separate announcement, ratings agency Standard & Poor’s assigned BlueScope a corporate rating of BB with a stable outlook, while its debt notes were given a BB- rating.

Moody’s Investor Services also assigned BlueScope Steel a corporate rating of Ba3 with a stable outlook.