A woman threw a shoe at Hillary Clinton in Las Vegas that the former US Secretary of State deftly dodged, cracked jokes about before continuing with her keynote address to a 1,000-plus audience.

The attacker, a middle-aged blonde woman, was immediately taken into custody by the Secret Service as the black and orange athletic shoe whizzed past at head height to the left of 66-year-old former First Lady.

The reason behind her act was not immediately known.

Clinton, who is widely expected to run for the 2016 presidential elections, had to duck during her keynote address at the annual convention of the Institute of Scrap Recycling Industries (ISRI).

"What was that, a bat?... Is that somebody throwing something at me?" Clinton asked, putting her right hand above her eyes to cut the glare of lights from the stage, Las Vegas Review Journal reported.

"Is that part of Cirque du Soleil?" she quipped amid laughter from the audience.

She was referring to the acrobatic dance troupe that has several shows in Vegas.

"My goodness, I didn't know that solid waste management was so controversial...Thank goodness she didn't play softball like I did," Clinton said, drawing cheers from the audience.

The Secret Service said the woman, who wished not to be identified, sneaked in the auditorium.

She was later arrested, the report said.

An ISRI spokesman said the woman was not a credentialed convention member and was not supposed to have been in the ballroom.

The most famous shoe-thrower in recent times has been the Iraqi journalist who hurled his two shoes at the then-US president George W Bush in Baghdad in 2008 during a press conference.