At the company's profit announcement in August, CEO Mark Vassella said market conditions were "unusually strong", leading to expected earnings in the first half of this financial year in the order of $1.8 billion to $2.0 billion.

Just two months later, the company has had to revise its expected half-year earnings to between $2.1 billion and $2.3 billion.

One of the key reasons is the favourable steel spreads - the difference between the cost of raw materials and the sale price of the finished steel.

The wider that gap, the more income for BlueScope.

"The performance continues to demonstrate the value of our business model, and further underpins our capacity to invest for long-term sustainable earnings and growth, to position the business for a low carbon future and to deliver solid returns to shareholders," Mr Vassella said.

In Australia, a continued increase in purchases of high-value products in the building and construction sectors has also helped to boost expected earnings.

Also, the North Star mill in the United States is experiencing better-than-expected prices for hot rolled coil.

The steelmaker will look to increase capital expenditure within the company - which may include the blast furnace reline at Port Kembla - while performance outstrips expectations.

Meanwhile, the company has also announced the appointment of two non-executive directors K'Lynne Johnson and Zhi-Qiang Zhang.

Ms Johnson will be based in the United States while Mr Zhi-Qiang will be close to the steelmaker's Asian market.

They will nominate for election at the 2022 annual general meeting.