The Opposition New Democrats say they've obtained internal government documents that only increase their suspicions that the Liberal government knew prior to last spring's election that a projected $495-million budget would actually be much higher.

NDP finance critic Bruce Ralston said Tuesday that the documents suggest the Liberals were aware of the mounting budget risks, but failed to disclose them to voters during the spring campaign.

Ralston said he has written to B.C. auditor general John Doyle, asking him to launch a review "with respect to government's responsibilities to the public to be open and truthful regarding deficits and spending."

Premier Gordon Campbell, whose government won a third consecutive mandate at the polls, maintained throughout the campaign that the deficit would remain at $495 million.

Then shortly after the vote the government announced that revenues had plummeted, and they tabled a revised budget with a record deficit of $2.8 billion.

"Given the ongoing public controversy surrounding the veracity of the government's fiscal promises prior to and during the 2009 election, we are writing to ask than an investigation be launched into this matter with a view to providing full public disclosure of what the government knew and when," said Ralston's letter to Doyle.

A spokeswoman at the auditor general's office said the NDP request had yet to arrive, making it premature to offer any comment.

Ralston said he obtained more than 300 pages of internal government documents though a Freedom of Information request made in May 2009 that suggest the government knew before the election that the deficit forecast was at risk.

But he said details are blanked out in the documents released under FOI legislation.

Among the documents are materials from a March 24, 2009 presentation entitled Monthly Finance Meeting. Ralston said the 14-page presentation is a series of blank pages, except for several intriguing headlines.

One page reads Risks to Forecasts.

Ralston said the FOI act requires government bodies to make public government information, including the type of information being withheld.

Finance Minister Colin Hansen would not comment Tuesday on whether or not he or his government knew during the campaign that their projected deficit would skyrocket. He has said in the past that he did not know until June.

He did say that the information that was withheld was from a briefing by the Treasury Board to a cabinet committee, which is bound by confidentiality.

And Hansen said ministry officials make the decision on what is released under an FOI request with "no political interference."

In any event, the documents in question relate to the previous year's budget, he said.

Ralston said the stack of mostly blank pages has done little to answer nagging questions about what the Liberals knew about the budget deficit before last year's election.

"That's my suspicion," he said. "If they want to disabuse me and other members of the public of that notion, the easy way to do it is release the documents rather than release blank sheets of paper."

The B.C. New Democrats are not immune to accusations of creative accounting around election time.

In 1996, the New Democrats were embroiled in what became known as the "fudge-it budget" scandal, where a surplus budget projected prior to the election became a deficit after the incumbent NDP won.

An investigation by the auditor general found the NDP based its surplus budget projections on overly optimistic revenue forecasts.

Ralston said the fudge-it budget was history.