Canada's most conservative province has elected a left-of-centre government, ending a 44-year-old conservative party dynasty.

Voters in the western oil-rich province of Alberta, sometimes called the Texas of the North, chose a New Democratic Party government in yesterday's election.

Few had predicted such a result just 28 days ago when the election was called by Progressive Conservative Alberta premier Jim Prentice, a former top cabinet minister in prime minister Stephen Harper's Conservative government.

"Pigs do fly," CTV television host Don Martin tweeted.

After the votes were tallied, Mr Prentice announced that he was finished with public life and was stepping down as the leader of the Progressive Conservatives in the province. He will also vacate the seat he won in the election.

"I think we might have made a little bit of history tonight," incoming New Democratic premier Rachel Notely said. "Change has finally come to Alberta."

Nelson Wiseman, a University of Toronto political science professor, said the result did not mean Mr Harper would not do well in his home province in October's national election.

Mr Wiseman said it showed the NDP was not as radical as it once was and that campaigns mattered. He said gaffes by Mr Prentice and voter fatigue with Alberta's Progressive Conservatives contributed.

"The main message is a social democratic party isn't all that radical any more. Americans are freaked out by socialism but when Tony Blair was in power in the UK they related to him as a strong ally," Mr Wiseman said.

Ms Notely has vowed to raise corporate tax rates and conduct a review of the province's royalty structure to ensure that Albertans are getting a fair return for their oil and gas resources.

Alberta has the world's third largest oil reserves, with 170 billion barrels of proven reserves.

Mr Prentice was previously one of Mr Harper's most trusted cabinet ministers and was tipped to replace him one day.