Republican Donald Trump's campaign of venom and audacity was underscored by bigotry, controversy and scandal.

The billionaire businessman's race to the White House has largely been characterised by shocking statements against immigrants from Mexico, Pakistan and Saudi Arabia.

The Republican candidate has also passed lewd comments against women and dismissed revelations of such comments as 'locker room banter'.

Trump's remarks on Islamophobia and his allegations of rival Clinton's drug use during the presidential debates last month are the most recent in a spate of comments that shocked people across the world.

As the world prepares for Trump's likely election to the White House, here's a recap of five of the most controversial statements made by the billionaire politician in the run-up the US presidential elections.

1. Boasting about sexual assault

During the final month leading up to the Nov 8 vote, the Trump campaign took a severe hit after the publication of a 2005 recording in which the Republican nominee boasted in vulgar terms about trying to have sex with an unidentified married woman and groping women, saying “when you're a star, they let you do it”.

Trump apologised for his comments, but also dismissed them as “locker room talk” and a distraction from the campaign.

In an attempt to prevent his campaign from falling apart, Trump expressed regret for making lewd comments about women.

"Anyone who knows me knows these words don't reflect who I am. I said it, I was wrong, and I apologise," he said in his video statement, posted on his Facebook page.

In the recorded conversation, Trump was wearing a microphone and chatting on a bus with Billy Bush, then host of NBC's “Access Hollywood” ahead of a segment they were about to tape.

"I did try and f*** her. She was married," Trump said. "I moved on her like a b***h, but I couldn't get there."

Trump talked about his attraction to beautiful women. “I just start kissing them,” he said.

"And when you're a star they let you do it," he said. "Grab them...you can do anything."

Following the leak, a number of women came forward with claims that Donald Trump had touched them inappropriately.

It was alleged that the Republic candidate had groped a woman in one instance and kissed a woman in another during separate encounters that took place as long as three decades ago.

In response, Trump denied that there was any truth to the claims.

2. Anti-Muslim statements

Trump has made headlines for spewing anti-Muslim rhetoric during his presidential campaign.

During the second presidential debate on October 9, Donald Trump was asked questions regarding rising Islamaphobia, the presidential nominee responded by pointing his finger at America's Muslim community.

"One thing we have to do is we have to make sure that because there is a problem, whether we like it or not — and we could be very politically correct, but whether we like it or not, there is a problem and we have to be sure that Muslims come in and report when they see something going on," stated Trump.

3. Pledge to suspend immigration

Donald Trump has said that people with roots in Pakistan, Afghanistan, Saudi Arabia and Somalia are a threat to the Western world and pledged to suspend immigration from regions with a proven history of terrorism.

Playing on America's fears after the San Bernardino shooting, Trump wasted little time in exploiting the tragedy.

4. 'Clinton was on drugs'

Trump added a stunning twist to the brutal White House when he challenged Democrat Hillary Clinton to a drug test before their next debate.

Trump suggested, without proof, that Clinton was “pumped up” on performance-enhancing drugs during the second presidential debate and insisted there be a drug test before the final debate that took place in Las Vegas on October 20.

5. Walls on the US-Mexico border

Early on in the race to the White House, Trump claimed if elected president, he would make Mexico build a wall along its US border.

On several occasions, the bombastic billionaire promised to crack down on illegal immigration and insulted Mexican immigrants by calling them rapists, criminals and drug dealers.