Tony Abbott is hedging his bets on who will be the next US president.
The prime minister met Republican prospect Jeb Bush in New York.
He was unable to catch up with the Democratic Party's Hillary Clinton while she was in New York at the same time, doing a book signing, but he telephoned her during a break between high-level meetings in Washington.
Mr Bush served as governor of Florida from 1999 to 2007.
He is the second son of former president George Bush and the younger brother of former president George W Bush.
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Mr Bush told reporters in early 2013 that he would make his decision on a tilt at the presidency "at least a year from now".
Pundits believe Mr Bush, along with New Jersey Governor Chris Christie, pose the toughest competition for the former secretary of state and first lady.
In her new book, Hard Choices, Ms Clinton writes that "women in public life still face an unfair double standard".
"Even leaders like former prime minister Julia Gillard of Australia have faced outrageous sexism which shouldn't be tolerated in any country," Ms Clinton says.
Mr Abbott told reporters that Ms Clinton had been a "highly creditable secretary of state, but beyond that I won't comment".
