A quarter of the way through its financial year the Government's operating balance (before valuation gains and losses) was $2.1 billion in the red, $450 million worse than forecast in the May Budget.

Tax revenue for the three months ended September 30 at $13.5 billion was $500 million, or 3.9 per cent, higher than in the same period last year.

The tax take from individuals, including the self-employed, was up $570 million and GST up $120 million, but corporate tax was $170 million lower than in the September 2011 quarter. Overall, tax revenue fell $300 million short of forecasts.

Core Crown spending at $17.3 billion was also below forecast, by $200 million, and just 0.3 per cent higher than in the same period last year.