The man who will take on Justin Trudeau has been elected by Canada's Conservative Party.

Andrew Scheer won the party leadership by the tiniest of margins, securing 51 per cent of the vote, to beat his main rival Maxime Bernier.

The 38-year-old will now lead the party- Canada's official opposition - against Mr Trudeau's Liberals in the 2019 general election, although he now has the difficult challenge of uniting his party first.

"We all know what it looks like when Conservatives are divided," Mr Scheer, who at 38, is seven-years younger the Canadian Prime Minister, told party members on securing victory.

"We will not let that happen again. We win when we are united. Imagine what we will do when we are all working together. We can’t go through another four years of Justin Trudeau.”