Officials in Texas have rejected claims of vote-flipping, following a tweet by GOP nominee Donald Trump that alleged the practice had taken place in the state.

Vote flipping happens when the voting machines change a voter's choice from one vote to another on the screen, either as part of a technical glitch or human error.

Trump had tweeted: "A lot of call-ins about vote flipping at the voting booths in Texas. People are not happy. BIG lines. What is going on?"

However, it is not believed that there have been no complaints of vote flipping coming from voters themselves, with local officials explaining the machines were functioning, and suggesting there could have been accidental voters errors.

Texas Secretary of State Carlos Casco also refuted the allegations of vote flipping, posting a statement on Facebook saying there had not been an issue with the machines.

Casco's Facebook statement, which his spokesperson told the Associated Press was made in response to rumours on social media, said: "Our office has received reports concerning rumours that some voting machines may be changing candidate selections when voters cast straight party ballots.

"We are actively monitoring the situation, and have yet to receive any verified reports of machines changing votes."

Trump has not made any further comments about vote flipping in Texas since his original tweet, but he has made several allegations of vote rigging over the past month.

In the third and final presidential election, Trump also suggested he may not accept the result of the election, because he believed it was rigged in Clinton's favour.

US president Barack Obama has previously criticised Trump's claim of vote rigging, stating: "That is both irresponsible and, by the way, doesn't really show the kind of leadership and toughness you want out of a president.

"You start whining before the game is even over? If whenever things are going badly for you and you lose, you start blaming someone else, then you don't have what it takes to be in this job."