Tim O'Neill said the government's announced revenue expectations are generally good and there is a reasonable amount of prudence built into the budget.
But he notes B.C.'s natural gas revenue forecasts have been significantly overstated for five of the last eight years and natural gas prices also are at records lows.
O'Neill's review comes one day before the Liberals table what they promise will be a balanced budget ahead of the May election.
In the throne speech last week, the government announced a decade-long plan to pay down B.C.'s debt using billions of dollars expected to flow in from natural gas production.
The Finance Ministry hired O'Neill in an effort to provide an independent assessment of the budget document.