Former US president George W Bush votes 'None of the Above' for next president

Former Republican President George W Bush and his wife, Laura, have not cast a vote for US president but voted for Republicans in down-ballot races, a spokesman for Bush has said.

"They voted 'None of the Above' for president," Freddy Ford said on Tuesday in an email about the couple, who now live in Dallas.

In a break from custom, neither George W Bush, president from 2001 to 2009, nor his father, former Republican President George HW Bush, endorsed the Republican nominee for president, New York businessman Donald Trump.

Jeb Bush, the younger brother of George W Bush and the son of George HW Bush, ran against Trump in the acrimonious and insult-laced Republican nominating contest this year.

Former secretary of state Hillary Clinton is the Democrat candidate this time.