The Government will release its Half Yearly Economic and Fiscal Update (HYEFU) on December 18.
Finance Minister Bill English appeared before Parliament's finance and expenditure select committee this morning.
He said the Government had maintained public services through the recession but that had meant deficits which could not continue.
"Debt of a nature which we can't continue with."
And there had been fluctuations in the Government's revenue take because of international impacts, English told the committee.
"We expect we'll continue to see patchy and somewhat grumpy growth for awhile."
The Government had continued to control spending but lower revenue affected performance in the last financial quarter, he said.
Labour finance spokesman David Parker said recent economic figures, including unemployment numbers, concerned the opposition.
English said the Government was always reviewing policy but "reality keeps turning out in different and unexpected ways".
The unemployment rate was generally too high, he said.
English said the HYEFU and Budget Policy Statement would set out the Government's wider economic programme.
The Government was on track for getting back to surplus in 2014/15, he said.
"We've set out a balanced programme of curbing new spending, returning to surplus and getting debt under control."
The Crown's net debt of $50 billion had helped support the economy through the recession.
"But this stimulus is expensive."
In difficult world markets it was essential to reduce debt, English said.