It appears panic has started to spread among Hillary Clinton voters as rival Donald Trump became the odds-on favourite to win the race for the White House.

A surprisingly strong showing from the Republican candidate has left the US presidential election on a knife-edge - and nervous Americans contemplating skipping the country.

The Immigration Canada website saw such a surge in visits over the last in the last hour that it completely crashed.

The page displayed an internal server error warning users "There is a problem with the resource you are looking for, and it cannot be displayed."

Twitter users were quick to spot the glitch.

Trump's success in key states such as Florida and North Carolina has seen the US dollar plunge and the Dow Jones fall by 500 points as election results trickled in.

Contests in other key battleground states were too close to call, severely denting Hillary Clinton's hopes of becoming the first female president in US history.

Google searches for "how to move to Canada" surged after Trump swept to victory in seven states on Super Tuesday.

The country is one of the most welcoming for immigrants and more than 20% of Canadians were foreign-born as of 2011.

Canada also has an express entry program for skilled immigrants and points are awarded based on your skills, education, languages you speak, and whether you have a job offer.