WINNIPEG -- Rookie politician, Indigenous rights activist and author Wab Kinew was elected leader of the Manitoba NDP Saturday, and vowed to rebuild the opposition party as he continues to face questions about his troubled past.

Party members elected Kinew, 35, over veteran cabinet minister Steve Ashton by almost a 3-1 margin -- 728 to 253.

"It's a new day for the NDP and it's a new day for Manitoba," Kinew declared to cheers following the vote. "This is a tremendous honour."

"I will take this role tremendously seriously and conduct myself with the greatest honour, integrity and honesty."

Within minutes of Kinew's victory, the governing Progressive Conservatives had a web site up that highlighted Kinew's decade-old criminal convictions, charges of domestic violence that were stayed, and rap lyrics with offensive terms for women, gays and lesbians and others.

Kinew, who was first elected to the legislature last year, told reporters he is willing to address attack ads.

"We know this is coming and what I'll do is I'll turn to my family, make sure they're OK, check in with my team and then I'll get right back to working on behalf of the people of Manitoba and standing up for their values."

Kinew went into the vote facing controversy over domestic violence charges that were stayed by the Crown in 2004 and only recently revealed.

The complainant in that case, Tara Hart, went public this week and told The Canadian Press that Kinew "flung" her across a room in the apartment they shared, which caused her to suffer severe rug burns.

Kinew said he never hit or threw Hart.

Kinew has also been convicted of assaulting a taxi driver and impaired driving more than a decade ago -- offences for which he recently received pardons.

"I am not the man I was," Kinew told delegates before the vote with his wife, Lisa Monkman, by his side.

"To my two sons ... be better than me. Be good men."

Kinew's only opponent, Ashton, had been using the revelations to try to swing delegates to his side up until the vote. He said Kinew's history would make it harder for him to lead the Opposition New Democrats into the next election slated for October 2020.

"If Wab Kinew is elected leader, we run the risk of the next election being about Wab Kinew," Ashton's campaign team wrote in an email to party members this week.

But Ashton did not criticize Kinew during his 30-minute speech before votes were cast Saturday. He focused his attention on Premier Brian Pallister's Tories, who were elected last year.

"Brian, if you're actually watching ... take a look around because we're going to make you the next one-term Conservative premier," Ashton said as he criticized Tory cuts to health care, changes to labour laws and a wage freeze being imposed on public-sector workers.

This was Ashton's third run at the party leadership. The 61-year-old ran unsuccessfully for leader in 2009 and 2015 and lost his legislature seat in last year's election. The 26 per cent of the vote he captured Saturday was the lowest of his three leadership bids.

Kinew replaces former premier Greg Selinger, who stepped down after the party lost the 2016 election to the Progressive Conservatives and saw 17 years in power come to an end.

The NDP currently holds 13 of the 57 legislature seats.

"I will carry forward the very important role of uniting the Manitoba NDP," Kinew told the crowd.

Kinew's large margin of victory will help reunite the NDP following a 2014 internal revolt that almost toppled Selinger, according to Paul Thomas, professor emeritus of political studies at the University of Manitoba.

"I think he can say, quite rightly, that he has a very strong mandate now to direct the party along the lines that he wants to see it go in."