Diana Whalen projected a deficit of $279 million for 2014-15 when she tabled the spring budget in April.
She had previously warned the province was in a tough financial situation because of an unexpected drop in revenues, higher departmental expenses and a one-time adjustment to the public service pension plan.
In June, audited financial statements for 2013-14 revealed the province's deficit had ballooned to $678.9 million.
That figure was up nearly $200 million from what was forecast in December 2013.
Whalen also said the net debt reached an all-time high of $14.8 billion.