NDP finance critic Bruce Ralston said the government's budget tabled in February was an attempt to mislead voters ahead of the May election.
"The B.C. Liberal government's election year budget is deliberately designed to hide a deficit of close to $800 million in the current year," Ralston said at a news conference in Vancouver.
"In our view they are artificially and deliberately suppressing expenditure growth in order to falsely claim a balanced budget."
Ralston said the government included unexplained asset sales to put the Liberals back in the black.
The latest provincial budget forecast a surplus of $197 million for 2013-2014, following several years of deficit spending that required the government to give itself an exemption from its balanced budget law.
Ralston likened the 2013 budget to the financial plan laid out by the Liberals ahead of the 2009 election, which turned out to be a deficit after the election.
Finance Minister Mike de Jong dismissed the claim as "political propaganda."
If the NDP have a plan, they should present it to British Columbians, de Jong said in an interview.
"The NDP, as always, wants to spend more," he said, which will lead to higher taxes, worsening credit and higher borrowing costs for B.C.
"I know the notion of fiscal discipline is extraordinarily foreign to the NDP — and it's always the taxpayers who pay for that — but to suggest that it can't be done is really to reveal how unprepared and unwilling the NDP are to bring that kind of fiscal discipline on behalf of taxpayers."
The Liberals said in a statement the last New Democrat government delivered eight consecutive deficit budgets, and the province received six consecutive credit-rating downgrades.
By 1999, the statement said B.C. had the highest top marginal personal income tax rate of 54 per cent for those earning in excess of $80,000 at the time.
The provincial Finance Ministry weighed in with a fact sheet pointing out that Moody's credit rating agency reaffirmed B.C.'s triple-A rating on Wednesday, citing the province's strong track record for meeting budget targets.
"After trailing the national average in real economic growth through the latter half of the 1990s and the early part of the 2000s, the British Columbia economy outperformed the Canadian economy in recent years," the ministry quoted Moody's as saying.
Ralston said the New Democrats will lay out a fiscal framework next week and it will be in the red, due to the deficit the next government will inherit.
"Our goal is to balance the budget within four years," he said.
Liberal expenditure growth is unrealistic unless there are massive cuts, he said, so the NDP plan will have higher expenditures. Those will be "fully costed" with new revenues, he said.
"Our proposals will be balanced, but we're starting from a point where the Liberals — if there is a change in government — will have left a real deficit," Ralston said.
Beside him, Carole James said the increases will be modest and fiscally responsible.
"This is being up front with the voters," James said, citing the 2009 Liberal budget.
"They were not up front with the voters and we believe it is critical to be honest and up front with the voters. That's what you see in these numbers."
James said additional spending on community living, health and post-secondary will be NDP priorities, but there were no other financial plans forthcoming.
If the New Democrats form the next government, Ralston said they would likely table a new budget in the fall with a plan to balance the books in four years.
Leader Adrian Dix has already said the party would increase income tax for high-income earners taking in more than $150,000 a year, and boost the general corporate tax to 12 per cent from 11 per cent.
They would also institute a capital tax on financial institutions to pay for non-refundable student grants.
Also on HuffPost