"Over the last few days, I have used some intemperate language that I regret," Martin, a longtime MP who is seeking re-election in Winnipeg-Centre, wrote in a statement on the weekend.
"I would like to offer an unreserved apology to my fellow candidates and to anyone else who may have taken offence to the tone and content of these remarks. I hope we can move past this and return to having a healthy discussion of the issues affecting Winnipeg-Centre voters."
Martin called Green party candidate Don Woodstock a "son of a bitch" last week during a candidates debate. In a Huffington Post article published Saturday, Martin was quoted as saying Liberal candidate Robert-Falcon Ouellette is a "political slut" because he had considered running for different political parties before settling on the Liberals.
Martin has represented the inner-city riding since 1997 and has a long history of speaking frankly. He stopped using Twitter after calling Conservatives "rat-faced whores."
None of Martin's words appear to have hurt his popularity to date. He has won an increasing share of the vote in his riding in every election since 1997 and has doubled his nearest opponent in the last three contests.
The Liberals, who finished a distant third in 2011 with 11 per cent of the vote, are working to convince people the race is close this time. They issued poll results that suggested the race has suddenly become neck-and-neck, although the poll was widely ignored by media because the Liberals did not say who conducted the poll and did not provide detailed data.
The Liberals have also tried to capitalize on accusations Martin lives on Saltspring Island in British Columbia. Martin has a cottage there, but lives just south of downtown Winnipeg, some 150 metres from his riding.
Ouellette, who surprised many when as a political neophyte last year he finished a strong third in the Winnipeg mayoral race, lives in the southern suburbs of Winnipeg.
Also on HuffPost