Former Liberal leader Paul Martin gestures at a heckler during a Calgary speech. (CBC)

Former Liberal prime minister Paul Martin raised some eyebrows in the oilpatch when he predicted the Liberals will form the next federal government.

In a spirited speech to about 100 Liberal supporters at the Calgary Chinese Cultural Centre on Friday, Martin attacked the Conservatives' economic record, while taking on a heckler.

"Who's the best economic manager?" began Martin, who was then interrupted when someone in the crowd answered, "Stephen Harper!"

The former Liberal leader shot back, with his voice rising: "Stephen Harper hasn't come up with a plan. If he's so good, why doesn't he come up with a plan? If he's the prime minister of this country, why is he afraid to deal with the issues?"

The partisan crowd cheered at Martin's feistiness in the heart of Conservative country.

"When we took office in 1993, the Conservatives left us with a $43 billion deficit. Four years later, that deficit was gone, and when we left office 2.5 years ago, there was a $12 billion surplus and no other country in the world can match that record," he continued.

'Let me simply say, on Oct. 14, we will elect a Liberal government.'— Paul Martin

"Let me simply say, on Oct. 14, we will elect a Liberal government."

Martin was back in his element, shaking hands and telling the crowd how glad he was to see them again.

When asked if he missed campaigning as a political leader, Martin said: "I've been there, done that. Time to go on to other things and I've been very clear that the aboriginal issues in Canada and Africa are where I'm going to be putting my time.

"But I am very worried about the Conservative record on the economy."

Martin, a lawyer and businessman, plans to spend the next few days in Calgary attending to what he called personal business interests.

Martin's Liberal government fell to the Conservatives under Stephen Harper in 2006 after 12 straight years of Liberal rule in Canada. Martin stepped down as Liberal leader after that defeat, but promised to finish his term as MP for the Montreal riding of LaSalle-Émard.