In the wake of federal Finance Minister Joe Oliver's unexpected decision to delay his pre-election budget until April at the earliest, the New Democrats want him to update the House of Commons on the state of the nation's finances.

NDP finance critic Nathan Cullen told reporters that his party intends to devote the first allotted Opposition day to a motion calling on the ruling Conservatives to "immediately present" an updated fiscal and economic forecast — one that would take into account what the New Democrats describe as "the unstable economic situation, including job losses, falling oil prices, and declining government revenues."

The motion would also instruct Oliver to ensure the budget "addresses the economic challenges faced by the middle class" by creating more full-time jobs while encouraging economic diversification.

A fresh fiscal update would serve as a "reality check" on the Canadian economy, Cullen told reporters.

He also heaped fresh criticism on what he described as "the wasteful and ineffective income-splitting scheme," which he said would help only a small percentage of Canadian families.

"There is no Plan B coming from the Conservatives," Cullen lamented.

Cullen said his party will also propose that both Oliver and Bank of Canada governor Stephen Poloz be invited to appear before the House finance committee to share their views on the state of the Canadian economy.

Income-splitting proposal 'a disaster': NDP

Oliver said earlier this month he won't deliver a budget before April due to instability caused by falling oil prices.

Last week, after a spate of bank reports warning of a downturn in the economy, the Bank of Canada cut its key lending rate by a quarter of a percentage point and predicted slower economic growth.

Today, a report from TD Economics predicted oil prices would continue to fall, pulling down growth in the short term, and said another interest rate cut is likely in March.

Government House leader Peter Van Loan also hit the microphones in the House of Commons foyer on Monday morning.

He affirmed the Conservatives will balance the budget this spring despite plummeting oil revenue and a weakening economy, and said the $3-billion contingency fund could be used to make that happen.

"Obviously yes, it becomes applied to the bottom line. If it's not spent on other things, it returns to the bottom line for the government," Van Loan said.

The NDP came out strongly against any move to use the contingency fund to boost budgetary coffers.

"While the policy of income-splitting is a disaster, it's not a natural disaster," Cullen pointed out.

Deputy NDP finance critic Guy Caron said the purpose of the contingency fund has always been clear.

"It's there for emergencies," he noted.

"If we start to change the definition of emergencies from natural disasters to intrangency on the part of the government, it could be used for a lot of things."

During question period, Liberal Leader Justin Trudeau challenged Oliver to reveal "exactly how much" the plummeting oil prices have cost the government so far.

When he declined to do so, Trudeau claimed the minister's staff had given him that information, "but he's choosing not to share it with Canadians."

Oliver, for his part, accused the Liberal leader of advising thousands of Canadians employed in the manufacturing sector to "find another job."

Government's flexibility impacted

The debate on the NDP motion is expected to take place on Tuesday.

The Liberals will get their own opportunity to set the Commons agenda on Thursday.

A spokesman for Oliver acknowledged that the "dramatic fall in oil prices will impact the government’s flexibility," but maintained that the government would balance the budget this year.

"Lower oil prices have varying implications for the economy, including lower prices at the pump, lower energy costs for manufacturers and increased global demand, especially from the U.S.," Nick Bergamini told CBC News via email.

"Canadians know that the NDP and Liberals would raise taxes on hard-working Canadian families and increase the national debt."