WASHINGTON (AFP) - Republican presidential nominee Donald Trump has edged ahead of Democratic rival Hillary Clinton by a point for the first time since May, an ABC News/Washington Post tracking poll out Tuesday (Nov 1) has found.

The poll also registered a seven point decline for Mrs Clinton in the share of likely voters who are strongly enthusiastic about her, a possible reflection of the renewed controversy over her use of a private server while serving as secretary of state, pollster Gary Langer said.

Mr Trump's 46-45 per cent lead in the four-way race for the White House, while well within the margin of error, is the first time he has polled ahead of Mrs Clinton in the survey since May.

The new poll was taken from Oct 27-30, a period that includes FBI director James Comey's Oct 28 announcement that his agents had found a new trove of e-mails that may be pertinent to an earlier probe into Mrs Clinton's handling of classified information.

The results flip 46-45 in the Democrat's favour when combining the last seven days, Mr Langer said.

"Either way the results are exceedingly close," he said.