Conservative leadership candidate Kevin O'Leary took time off from the campaign trail this week to pitch his "exclusive" wines on an American home shopping channel, prompting accusations from at least one rival that he's simply not a serious contender.

O'Leary was featured on an hour-long "today special value" segment of QVC, where he extolled the virtues of his reserve wines, selling some 7,500 cases of red, white and rosé blended wines to U.S. shoppers, while sipping the product alongside the show's two co-hosts.

"I know why they call you Mr. Wonderful now, because you make some wonderful wine," said Mike, a caller to the program. "Keep bringing us the delicious wines, Kevin, we enjoy you on QVC and we enjoy you on Shark Tank," said another caller, Nancy from California. QVC segments are taped from the company's studios in West Chester, Penn.

"Blending wine is half art, half science, and I'm getting better all the time. Whatever I bring forward, I put my name on it, it's going to be amazing, I have your back," O'Leary said while hawking his wares.

O'Leary writes on his website that he created O'Leary Fine Wines "to help give Americans access to amazing wine at an amazing price." ​A three-bottle set of O'Leary's wine was sold by QVC for $43 U.S. with free shipping and handling.

Kevin O'Leary wine

O'Leary tends a grape vine in a photo posted on the QVC home shopping channel website. (QVC/CBC)

The Montreal-born businessman has faced criticism for the amount of time he spends in the U.S. while running for Canadian political office, prompting comparisons to former Liberal leader Michael Ignatieff, who spent decades south of the border and in the U.K. before returning home to what was ultimately a stinging electoral defeat.

"He's utilizing the leadership race for self-promotion, absolutely, no question about it," said Ontario Conservative MP Lisa Raitt, who is also running for the leadership.

"He shouldn't be trying to fit the leadership race into his busy work schedule or fit it around his publicity appearances on Shark Tank, or QVC, or whatever it might be. This isn't a part-time job, being leader, or prime minister, and you have to take it serious."

'Boston is home'

O'Leary has said he spends more than 180 days out of the country each year, primarily in the U.S.. Earlier this month, for example, O'Leary rang the closing bell on the New York Stock Exchange, after one of his exchange-traded funds made its debut.

On Friday, he made an appearance on U.S. television network CNBC, where he defended President Donald Trump's performance so far in a heated exchange with Mark Cuban. He told the Dallas Mavericks owner not to fear Trump because "we" have checks and balances to protect against executive power abuses.

O'Leary owns property in both Toronto and Boston, but in a 2013 interview with Boston Magazine he said "Boston is home."

Raitt has been a strong critic of the former Dragon's Den star in the past and set up the website StopKevinOLeary.com. She said O'Leary needs to be in Canada to meet with actual Conservative Party members and that he shouldn't rely on pitching his message to voters through appearances on American television.

O'Leary wine

A campaign spokesman said O'Leary was contractually obligated to make the television appearance with QVC. (QVC/CBC)

"People who are running to be leader should be taking it as serious as the people who are casting their ballots, and I don't see that equilibrium with Kevin O'Leary. Canadians wants to be heard," she said. "He only got into the race in the last three weeks, surely he can take some time off to deal with the issue at hand."

Ari Laskin, O'Leary's campaign spokesman, said it's "easy" and "hypocritical" for other leadership candidates to criticize his candidate when many of them, including Raitt, have kept their full-time jobs as members of Parliament while running for the leadership.

"Mr. O'Leary has a day job that does take him around the globe. Many of the contracted appearances in the U.S. were booked years in advance, and as such he is obligated to appear," Laskin said in an email to CBC News.

O'Leary will not attend a leadership debate in Langley, B.C., this Saturday, the only registered candidate to skip the event. His campaign told CBC News there was a conflict with other campaign events.

"Mr. O'Leary is 100 per cent committed to the Conservative Party of Canada and will continue to speak with current and new members," Laskin said.

The federal Conservatives will elect their new leader on May 27.