Bluescope Steel has lifted its first-half earnings guidance about 12 per cent largely thanks to a strong performance in North America.

The company expects underlying earnings before interest and tax for the six months to June 30 of about $680 million, compared to February’s guidance of $606 million.

The increase was mainly due to Bluescope’s North Star mini-mill in Ohio, although higher margins on export coke sales also helped its Australian steel business.