Canadian MP Maxime Bernier has quit the Conservative Party of Canada and says he will form his own party devoted to "more freedom, less government".

He says his party will be ready in time for the October 2019 federal election.

Mr Bernier lost the Conservative leadership race in May by a small margin to current leader Andrew Scheer.

In recent weeks, he has launched Twitter attacks against PM Justin Trudeau's "extreme multiculturalism" and immigration policy.

In front of a packed and expectant press conference on Thursday, Mr Bernier announced he is leaving the federal conservative caucus.

He said he has not spoken to any other Conservative members of parliament about leaving the caucus for his as-yet unnamed party.

"I want to do politics differently," he said. "I will find another way to give a voice to millions of Canadians. I will continue to fight for freedom, responsibility, fairness and respect."

He has served as a Conservative MP for the Quebec constituency of Beauce for the past dozen years, and will remain an independent MP in the House of Commons.

"I have come to realise over the past year that this party is too intellectually and morally corrupt to be reformed," he said.

Mr Bernier says his decision was made in part because the party told him to "shut up" when he attacked Mr Trudeau's immigration and diversity policies.

Mr Bernier also challenged the party's support for Canada's system of supply management in the agricultural sector, a system that has also been derided by US President Donald Trump and become a sticking point in Nafta negotiations.

Mr Bernier had previously served as foreign affairs minister under the government of Stephen Harper, but resigned after it was discovered that he left confidential documents at the home of his ex-girlfriend, who had ties to organised crime figures.

In response to Mr Bernier's decision to leave the party, Mr Scheer said: "He has chosen to put himself above all things".