Finance Minister Bill English downplayed a $1.4 billion improvement in the Government's latest monthly accounts, saying it does not lessen the Government's need to keep control of its spending.
The deficit before gains and losses on the Government's investments was $5.9 billion to the end of April, $1.4 billion dollars less than forecast in the Budget in May.
The deficit was smaller due to a higher than expected tax take and lower than expected spending.
The tax take was $770 million more than forecast. But Mr English says tax is still nearly $1 billion down on the Treasury's pre-election forecasts in October last year.
Mr English says a tight rein on spending is still needed to hit the Government's target of a surplus by 2014-15.
The minister says the Government knows where the money is going, but the revenue is uncertain and this month it has been higher than expected. The big task is to do everything possible to lift economic growth.
Returns from State Owned Enterprises and Crown Entities were $300 million more than forecast, while spending was $320 lower than predicted.
The Green Party says the new figures showing stronger-than-expected returns from SOEs is further proof the Government should retain them in full ownership.
The Treasury says company tax was $450 million more than it forecast in the Budget. Crown expenses were 0.6% lower than expected. The debt balance is slightly better than forecast at 25.9% of gross domestic product.
Infometrics economist Benje Patterson says the better-than-forecast deficit does not signal a dramatic turnaround in the Government's books and more spending cuts will be needed to hit the surplus target.