Emerson, a former business executive and British Columbia official, told the Canadian Broadcasting Corp. he agreed to be one of the national co-chairmen of the Tories' election campaign.

Canadian Prime Minister Stephen Harper is expected soon to call an election for next month.

Emerson announced Thursday he wouldn't seek re-election -- one of three Tory ministers announcing they wouldn't seek re-election.

He cited his family and the the toll traveling takes as reasons for his decision, the CBC said.

Emerson was twice elected as a Liberal in British Columbia's Vancouver Kingsway federal electoral district before joining the Conservatives less than a month after the 2006 election, which led to Canada's first Conservative government since 1993.

In crossing the floor, he became the first Canadian Parliament member to take his seat in a newly elected Parliament as a member of a party opposed to the party under whose banner he won the seat, the CBC report said.