Hillary Clinton would make a fine US president, Barack Obama told reporters on Saturday, on the eve of the expected launch of her candidacy for the Democratic Party"s nod in 2016.

Obama beat Clinton -- who is vying to become the first woman president of the United States -- for their party"s nomination in 2008 after a grueling campaign. He then won re-election four years later.

"She was a formidable candidate in 2008. She was a great supporter of mine in the general election. She was an outstanding secretary of state. She is my friend," Obama said at a regional summit in Panama.