SYDNEY – Australian Prime Minister Malcolm Turnbull said on Friday he is hopeful of securing an exemption from U.S. tariffs on steel and aluminium after sustained lobby effort by his government.

US President Donald Trump on Thursday imposed a 25% tariff on steel imports and 10% for aluminium on Thursday.

But as Trump backed away on earlier pledges of tariffs on all countries by exempting imports Canada and Mexico, he signalled Australia could also secure favourable access, a boost the country's only exporter BlueScope Steel.

"I was very pleased to see the president acknowledge explicitly today, the strong points that I've been making to him and my colleagues have been making to his ministers, the Defence Secretary, the Treasury Secretary and many people in the White House," Turnbull told reporters in Sydney.

"Whatever complaints the United States may have about other trading relationships, it has no complaints with respect to Australia."

Despite being one of the world's largest suppliers of raw commodity, iron ore, it is a small global exporter of steel.

Australian steel and aluminium to the United States were worth just over A$400-million last year, government data shows.

Turnbull in late last month travelled to Washington for talks with Trump where the issue of tariffs was discussed.

Australia has won favour with the United States for its commitment to military expansion in the region.

Trump highlighted close ties with Australia when pressed on the possibility of further exemptions.

"We have a very good relationship with Australia," Trump told reporters in Washington. "It is a great country, a long-term partner, we will doing something with them."

BlueScope Steel said an exemption would help boost exports to the United States the company but warned it could be hurt as exporters seek new markets for their products.

"The concern for us is the dislocation of any steel out of North America and any other market," said Mark Vassella, MD and CEO of BlueScope Steel.