Provincial Liberals in Newfoundland and Labrador brought in some star power to their weekend convention in Gander, with federal party leader Michael Ignatieff issuing a warning to Prime Minister Stephen Harper.

Michael Ignatieff, seen here Saturday night on the convention's final day in Gander, said he's personally unfazed by the Conservative TV ads. (Carolyn Ray/CBC)

"If you mess with me, I will mess with you until I'm done," Ignatieff said Saturday.

He said the new Conservative TV ads attacking his commitment to Canada don't bother him on a personal level. Ignatieff said they're offensive because they attempt to define who is and who isn't a good Canadian, based on the amount of time they've lived in Canada.

The television ads point out that Ignatieff spent 34 years outside Canada and accuse him of having "no long-term commitment" to the country.

In a video posted on YouTube last week, Ignatieff dismissed the ads as "spite and spin."

Ignatieff told his audience in Gander he plans a different approach as he takes on the prime minister.

"Let's be clear how we carry the attack, because I will not attack Mr. Harper's patriotism. I will not attack his character. I will not attack his family. I will attack his record, and God knows, there's enough to work on," he said.

More than 300 people attended the Liberal gathering for the biggest convention of its kind in years. The Liberals may be the official opposition at the provincial level, but they have only three out of 48 seats, so this is a time of rebuilding.

Leader Yvonne Jones said Ignatieff offered her some good advice.

"You know he looked at me this evening and he said, 'Yvonne, I have been where you are. And I know what it's like, and I know that it's tough, but you hang tough and you keep doing what you're doing, because you're making a difference.'

"To me that's very inspiring when it comes from a man like him, who I know today, will be the next prime minister of this country," she said.

Both Jones and Ignatieff stressed the importance of united politics as a strong way to gain the public's trust. In a province where the relationship with the federal government is strained, Ignatieff extended an olive branch.

"The prime minister of Canada has only one job, and that is to unite Canadians and never divide them, and that, Mr. Harper does not understand," Ignatieff said.

With files from The Canadian Press