Federal cabinet ministers David Emerson, left, Loyola Hearn, centre, and Monte Solberg will not seek re-election, the Conservative party confirmed Thursday. (Sean Kilpatrick/Fred Chartrand/Canadian Press)

Three cabinet ministers — David Emerson, Loyola Hearn and Monte Solberg — will not run in the next election, the Conservative Party of Canada announced Thursday afternoon.

"I have the utmost respect for all of these men and wish both them and their families all the best with whatever they choose to do outside of politics," said Prime Minister Stephen Harper in a news release.

All three will play key roles in the looming campaign, the release said.

Both Emerson, the Foreign Affairs minister, and Hearn, the Fisheries minister, were widely expected to step out of politics in the next electoral race, but Solberg's departure came as a surprise.

Solberg served as a Member of Parliament for Medicine Hat for the past 15 years, and spent the past two years in cabinet posts. He was Citizenship and Immigration minister before being appointed to the Human Resources portfolio in cabinet shuffle in early 2007.

"The decision to retire is the most difficult decision that I can remember making," Solberg wrote on his high-profile blog. He gave no indication what triggered his decision.

Emerson, who represents the Vancouver-Kingsway riding, made headlines when he defected to the Tories in February 2006, less than a month after winning a seat as a Liberal in the federal election.

His crossing of the floor gave the Conservatives an MP with strong business experience — Emerson once served as CEO of the softwood lumber giant Canfor Corp. and had been industry minister under Liberal prime minister Paul Martin.

Emerson said Thursday Harper had known for a year it was unlikely he would seek re-election.

"I've committed to the prime minister to continue to support him and serve in any way he may think is valuable," he said, denying speculation that he dropped out because he wouldn't be able to win his Vancouver Kingsway riding.

Instead, Emerson said he made the decision with his family a while back that he would only serve one four-year term as an MP.

"I've got a young family, we've got kids still in school," he said. He did not indicate how he would remain involved with the Conservatives after the election.

Emerson was initially appointed the Conservatives' international trade minister, and he was praised for signing a softwood lumber agreement with the United States, ending a longstanding trade dispute.

Hearn represents the Newfoundland riding of St. John's South-Mount Pearl and has been an MP since 2000.

Since then, he has battled Newfoundland and Labrador Premier Danny Williams over equalization and defended seal hunters in his province.

The prime minister is expected to pull the plug on his minority Conservative government on Sunday, with Canadians then going to the polls on Oct. 14.

With files from the Canadian Press