Canadians will see a "fundamentally different approach to the economy," when the Liberal government unveils its 2016 budget next week, says Francois-Philippe Champagne, the parliamentary secretary to the minister of finance.

"This (budget) is one of investing in Canadians, investing in growth, investing in families," Champagne told CTV's Question Period. "We want to grow the economy for long term, sustainable growth. That's what Canadians want."

The budget, which will be tabled on Tuesday, is expected to address a wide array of Liberal promises and priorities, from increased infrastructure spending to affordable housing.

The party campaigned on a platform that pledged to take on federal deficit in order to increase spending in some areas. But amid low oil prices, a faltering loonie, and competing requests for funding, the projected deficit has ballooned.

Analysts project Tuesday's budget will see a deficit in the tens of billions, and Finance Minister Bill Morneau pinned the number at $18.4 billion at the end of last month.

The growing shortfall has drawn intense criticism from the Conservative opposition.

"The Liberals have a fundamentally backwards approach," Conservative House Leader Andrew Scheer told CTV's Question Period. "If spending money for the sake of spending money would stimulate the economy then there wouldn't have been crises in Greece and Europe."

Scheer accused the Liberals of treating the "symptoms," rather than the causes of Canada's economic woes.

"They're ignoring private sector solutions, and thinking that government spending can solve all these problems," he said.

Scheer touted the previous Conservative government's economic record, and said the Liberals need to focus more on promoting private sector projects such as pipelines or the proposed Toronto Island Airport expansion.

But Champagne defended his government's approach.

"If the Conservatives were in power today … you would see cuts and cuts to balance the budget at all costs," he said. "Our priority is about growth."

Helping the 'people who really need it'

Meanwhile, NDP Deputy House Leader Matthew Dube said his party hopes the upcoming budget will do more to address Canada' growing inequality.

"It's already something we've seen as a problem," he said.

Dube commended the Liberals for cancelling plans to raise the age of eligibility for Old Age Security benefits to 67, but implored the government to place a greater focus specifically on "our poorest seniors."

He also called on the Liberals to address access to Employment Insurance, and to provide a clear plan for how increased infrastructure spending will work.

"It's one thing to throw money at a problem," Dube said. "But … what kind of criteria will be in place? Will they … allow the money to flow to the communities that need it? That's going to be really important to see."