SYDNEY (Reuters) -Australia on Wednesday said it was "really disappointing" U.S. President Donald Trump did not give it exemptions on steel and aluminium tariffs, but vowed to continue lobbying the U.S. administration for a reprieve.

Trump said in February he would "give great consideration" to exempting Australia from the tariffs in view of the U.S. annual trade surplus with the country, following a phone call with Australian Prime Minister Anthony Albanese.

However, on Tuesday the White House announced that the previously planned 25% tariffs on all imported steel and aluminium products into the U.S. from all countries would take effect on Wednesday - with no exceptions or exemptions.

Australian Deputy Prime Minister Richard Marles said his government would continue to press the Trump administration for an exemption.

"Well, obviously it's really disappointing news," Marles told radio station 2GB.

"Tariffs don't make any sense, it's an act of kind of economic self-harm. We'll be able to find other markets for our steel and our aluminium and we have been diversifying those markets."

During his first presidential term, Trump exempted Australia from U.S. tariffs on steel and aluminium.

"Last time around it was nine months before we got an exemption in relation to steel and aluminium out of the Trump administration in its first term. So, we'll keep pressing the case," Marles said.

Trump on Tuesday threatened to make the tariffs for Canada 50%, but reversed course just hours after announcing the higher tariffs, in rapid-fire moves that scrambled financial markets.

A key U.S. security ally in the Indo-Pacific, Australia is a small global exporter of steel although it is the world's largest exporter of the main steelmaking raw material iron ore. Australia accounts for only around 1% of steel imports into the U.S. and 2% of its aluminium imports.

(Reporting by Renju Jose in Sydney; Editing by Richard Chang and Lincoln Feast.)