Hillary Clinton has a sizable lead over Donald Trump in Florida, but her lead gets cut in half when third-party candidates are included.

In a head-to-head matchup among likely Florida voters, Clinton leads Trump, 47-40, according to a new University of North Florida poll.

However with Libertarian Gary Johnson and Green Party Jill Stein in the race, Clinton's lead shrinks to just 3 points, 41 to 38 percent, which is well within the margin of error of 3.8 percentage points. In that matchup, Johnson gets 6 percent, Stein has 3 percent and 10 percent are undecided.

"This suggests that the Clinton campaign should perhaps perceive Johnson as a threat, who is taking more votes from her than Trump," said Michael Binder, faculty director of UNF's Public Opinion Research Laboratory.

The UNF poll is the third major survey that shows Clinton ahead of Trump since the first presidential debate more than a week ago. The poll also found that though neither major party candidate is well-liked, Trump is disliked more.

Clinton is viewed unfavorably by 53 percent and favorably by 43 percent, making her net favorability rating -10. Trump's rating is -23, as 60 have an unfavorable view of him and 37 percent view him favorably.

The poll of 696 registered likely Florida voters was conducted Sept. 27 through Oct 4 with a margin of error of plus or minus 3.8 percentage points.