Next week's budget will lay the groundwork for long-term economic growth by investing in "unsexy" but much-needed infrastructure projects, Prime Minister Justin Trudeau said today.

During a town hall with Bloomberg TV in New York, Trudeau also confirmed that Tuesday's federal spending plan will reverse the eligibility for Old Age Security to 65 from 67.

Trudeau called former prime minister Stephen Harper's move to phase in a two-year increase in the retirement age a "simplistic solution to a complex problem that won't work."

Responding to a demographic shift to an aging population will require a broad strategy that includes promoting healthy lifestyles and activity to creating links between older, more experienced mentors and younger Canadians, he said.

"There's a bundle of things to look at, but the place that we are returning to, because it was a mistake to bounce it up to 67, is we're starting from 65," the prime minister told Bloomberg's John Micklethwait.

The Conservative plan to raise the age to 67 was not set to kick in until 2023.

The party's employment, workforce and labour critic, Gérard Deltell, slammed the decision he says was made for "bad political reasons." He said it will cost future generations of Canadians.

"It's the wrong call for the economy and the wrong call for the people because at 65 years old people are still in good shape and many of them would like to continue to work," he said. "Putting the retirement age at 67 was the most responsible way."

Investment over austerity

Trudeau said the Liberal plan to grow the economy rejects the "austerity" trend and is based on the premise that government has an effective role to play in stirring the economy. That plan is much different than the Conservative government's massive stimulus plan that responded to the 2008-2009 recession.

"What we're looking at is not so much trying to jolt the economy into life, as trying to lay the groundwork, the foundation for better productivity over the long term, and not just an influx of cash," he said.

Municipal projects like maintenance and upgrades "don't get the flash" but are desperately needed to create jobs and build for the future, he said.

Deficit promise won election

Trudeau said he believes his promise to run deficits won him the fall federal election.

"We had made that announcement, and the left-wing New Democratic Party had announced they were going to balance the budget at all costs, just like the Conservative government," he said. "The day we said, 'No, it's time to invest in the future of our country' and they confirmed they weren't, I got home to my wife and I said: 'I'm pretty sure we just won the election.'"

During the campaign on Aug. 27, 2015, Trudeau said a Liberal government would not balance the books for three years straight, but would double spending on infrastructure to stir economic growth.

At that time, he promised a "modest short-term deficit" of less than $10 billion for each of the first three years, though that figure is now expected to be much higher in next week's budget.

Economy a challenge and opportunity

Trudeau said the transforming economy — with a collapse in oil prices and a global response to climate change — should be viewed not just as a challenge, but an opportunity. 

"Right now, the frame we've put forward and the frame we'll be putting forward in the budget next week is the one that is suited to our economy and the example I think we can give to the world: That we should be investing, that we should be using fiscal levers a little more and not just expecting monetary policy for the challenges we're in," he said. "Because I think we're approaching the limits of the impact of monetary policy alone."

Trudeau insisted Canada can still be a leader on tackling climate change despite being an oil-producing nation, and said the "genius" of a federation is the ability to apply different solutions in different parts of the country.

"I don't particularly worry about what type of carbon-pricing mechanism a given province is going to bring in, as long as they're reaching the reductions that they're committing to," he said.

Earlier this month, Trudeau and the provincial premiers met in Vancouver  to map out a pan-Canada strategy on climate change. They agreed to look at mechanisms that included carbon pricing, with more details to be worked out after more talks and study.

Bombardier bailout

Trudeau was also asked by Bloomberg about a possible bailout for troubled plane-maker Bombardier.

The province of Quebec, where the company has its headquarters, unveiled a $1-billion investment in Bombardier's CSeries passenger jet last October and called on the federal government to do the same to help protect thousands of jobs.

Trudeau says Ottawa taking its time on a Bombardier bailout0:34

But Trudeau would not commit to a quick decision, insisting the government is taking a "deliberate and thoughtful" approach that would balance the interests of the aerospace industry as well as taxpayers.

"We are very much looking at this as what is the right investment and is it a smart investment for Canadian jobs for the Canadian economy and for the global market and that's the lens we're taking on that decision and that's why we're taking our time with it," he said.

The prime minister also weighed in on the U.S. election, saying, 'We'll see what Americans are made of' in the presidential vote.

Common ground with Trump

In spite of Republican front-runner Donald Trump's hard-line stands on security and refugees, Trudeau said he has common ground on some key issues.

Trudeau on Trump and US Canada relations2:22

"A desire to see Americans do well. A desire to see citizens in our countries have better jobs and greater opportunities," he said. "When you come down on a frame that says 'Let's create success,' well then you get to discuss what the best way to create that success is."

Trudeau is also meeting with the president and CEO of Thomson Reuters, then he will participate in a roundtable with Canadian female business leaders.

Last night, Trudeau was honoured at a gala dinner by non-profit organization Catalyst for his efforts to promote gender equality.