The steelmaker's CEO Mark Vassella on Monday reported a $1.015 billion profit after tax for the 2019 financial year.

While an impressive result, it was down on last year's $1.5 billion return.

He said much of the $500 million drop was account-keeping - writing up the value of assets that had previously been written down.

Mr Vassella pointed to the before-tax earnings of $1.3 billion as a better indicator of how the steelmaker was travelling.

That figure was up $79 million on the last financial year and it's the third consecutive year the before-tax take was over $1.1 billion.

"We are now a resilient global company with a strong balance sheet and high-quality assets which provide the capacity to withstand and potentially take advantage of tough cyclical conditions," Mr Vassella said.

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"Globally there are some challenges; the steel industry remains in over-capacity and trade action is creating volatility."

An indicator of the health of the company was Monday's announcement BlueScope will spend $US700 million upgrading its North Star mill in Ohio, USA.

"This is a brilliant business," Mr Vassella said.

"It's well-located, it's close to its source of scrap and it sells out 100 per cent of its product within a pretty close proximity to the mill."

The expansion will see the mill produce an extra 850 kilotonnes of hot rolled coil each year and Mr Vassella expected the bulk of that to be sold in the same market.

The returns in the Australian Steel Products division - which includes the Port Kembla steelworks - were down.

The division had before-tax earnings of $535.4 million, down 9 per cent on last year's result.

"Conditions in Australia in the back half of the year weakened due to a combination of falling steel prices and softer demand," Mr Vassella said.

"We saw some softening of demand in the residential market, in detached and semi-detached housing; and alterations and additions - the segments where we're selling our higher value-add products like Colorbond, the wind-back was moderate and from a high base."

Mr Vassella said the Australian division had a good first month of the new financial year.

He was "cautiously optimistic" about a "modest" improvement in volume coming from the second half of the year.

Across the business, weaker steel spreads were expected to see a 45 per cent half-year drop in before-tax profit.