Senator John McCain, who was also the Republican nominee for president in 2008, called Hockey to smooth over relations.
"I called Australia's ambassador to the United States this morning to express my unwavering support for the US-Australia alliance," McCain, who has frequently criticised Trump, said in a statement.
McCain added that he asked Hockey to "convey to the people of Australia" that Americans value their alliance, "honour the sacrifice of the Australians who have served and are serving by our side, and remain committed to the safer, freer, and better world that Australia does far more than its fair share to protect and promote".
Senator Bob Corker of Tennessee said in a tweet that he and Hockey had "discussed the important and long-lasting alliance between our two countries".
Earlier, Trump took another swipe at Australia, accusing the nation of "really terribly taking advantage" of the United States.
Speaking to reporters overnight at the White House, Trump again blasted the refugee deal negotiated by Australian Prime Minister Malcolm Turnbull last year with former US President Barack Obama.
Obama agreed to allow 1250 refugees from Manus Island and Nauru to be permanently settled in the US, an arrangement Trump has slammed as a "dumb deal".
Speaking overnight of his plans to renegotiate deals with other nations, Trump said: "Even countries who are allies, a lot of countries are taking advantage of us, really terribly taking advantage of us.
"We have one instance in Australia - I have a lot of respect for Australia, I love Australia as a country.
"We had a problem: For whatever reason, President Obama said we could take probably well over 1000 illegal immigrants who are in prisons, and then we are going to take them into this country and I just said, 'Why?'
"I asked that question and I can ask that question of you: Why?"
Despite Trump's White House spokesman confirming in a press conference overnight that the US would honour the refugee arrangement, Trump told reporters that he couldn't see the purpose of the deal and said, "We'll see what happens."
"If the previous administration does something you have to respect that," Trump said.
"But you can also say, 'Why are we doing this?' That's why we are in the jams that we are in."
It comes after the President defended his tough stance at the National Prayer Breakfast, assuring Americans they shouldn't worry about his "tough" phone calls with world leaders.
Trump told the prayer breakfast that the US was being taken for a ride, but promised his administration would "straighten it out".
"When you hear about the tough phone calls I'm having, don't worry about it," Trump told the audience.
"Just don't worry about it.
"They're tough. We have to be tough.
"It's time we have to be a little tough, folks.
"We are taken advantage of by every nation in the world virtually. It's not going to happen anymore."
