BlueScope Steel still doesn't know what may come from its efforts to win an exemption from US President Donald Trump's planned tariffs on imported steel.
BlueScope ships steel from Australia to its operations in the US, which produce metal-coated steel and painted steel coils for building and construction.
President Trump has announced plans to impose a 25 per cent tariff on imported steel and a 10 per cent tariff on imported aluminium, which has sparked concerns the impost could lead to a trade war.
BlueScope chief executive Mark Vassella said on Wednesday that President Trump's proposal had created uncertainty.
"It's been very hard for us to get a line on this," Mr Vassella told reporters at a business forum in Sydney.
He said BlueScope has had plenty of support from Prime Minister Malcolm Turnbull, Trade Minister Steve Ciobo and Australia's ambassador to the US, Joe Hockey.
"But again, until the decision's made, it's hard for us to speculate," Mr Vassella said.
"All we could really do is put our best foot forward."
Mr Vassella said BlueScope has obtained a fair hearing from the Trump administration, and given every chance to put forward its case for an exemption.
He said the US economy remains very strong and BlueScope has a lot of money invested there.
"Our expectation is we will continue to grow and invest in that country," Mr Vassella said.
Reserve Bank of Australia governor Phillip Lowe described President Trump's tariff announcement as "highly regrettable and bad policy".
"History is very clear here: protectionism is costly," Dr Lowe told the business forum.
"It is costly to the country that implements the protectionism, it is costly to everyone else - it is just not the right thing to do."
