Shona Holmes says she would have died had she relied on the Canadian health-care system and waited to see a specialist about her brain tumour. (CBC)

An Ontario woman featured in a new U.S. ad warning Americans about embracing Canadian-style health care said she believes it's important to speak out against the problems in the system.

"We're not speaking up about what the problems are in it," Shona Holmes, who went to the U.S. to be treated for a rare type of cyst at the base of the brain, told CBC Newsworld.

Holmes, from Waterdown, Ont., said she would have died had she relied on the Canadian health-care system and waited to see a specialist. Instead, she mortgaged her home, paid $100,000 and was treated at the Mayo Clinic in Arizona. She is currently suing OHIP to recoup those costs.

"Every time that I decide I'm not going to do anything more for this situation or the cause – not this particular ad campaign, I don’t meant that – but about speaking out against our health-care system, I get another really sad phone call or desperate phone call of somebody who is tragically trying to get treatment in Canada and can't.

"And I felt that I really had a responsibility to speak out."

The advertisement is being run by a conservative group opposed to U.S. President Barack Obama's plan to involve the government playing a role in reforming U.S. health care.

The advertisement warns that Washington wants to bring in Canadian-style health care that would cause "deadly" delays for people waiting for important medical procedures.

"I am a Canadian citizen, and as my brain tumour [sic] got worse, my government health-care system told me I had to wait six months to see a specialist," Holmes says in the commercial. "In six months I would have died."

The sponsor of the ad, Patients United Now, is an offshoot of the Americans for Prosperity Foundation, a privately funded, Washington-based conservative group that believes in limited government and cutting taxes. It is one of a handful of commercials that are expected to grow in number and criticism this summer as detailed health bills emerge from the U.S. Congress and dozens of interest groups, companies and labour unions tussle to influence legislators.

Holmes said it feels good to speak up because she has experienced health care on both sides of the border.

She said there are good things about the Canadian system as well as bad, and that Canadians have heard all the negative stories about U.S. health care.

"Americans have a very different idea of what the Canadian health-care system is. And the No. 1 thing is they think it is free."

Holmes stressed that she is not anti-Canadian, but that people should not be afraid to have a dialogue about health care.

"I think it's time we all started to talk," she said.

With files from The Associated Press