"The spotlight will be on Government expenditure or putting up tax - a difficult choice to make."
Mr Ebert was commenting on the latest Crown accounts released by Treasury which showed tax revenue for the four months ended October, at $16.8 billion, was $1.1 billion, or 6.3%, down on forecast.
The operating balance excluding gains and losses (obegal) was a deficit of $4.4 billion, up more than 79% on forecast.
The operating balance was a deficit of $2.2 billion, up 25.6% on forecast.
Corporate tax revenue was $784 million (28%) lower than forecast, mostly due to a slower economic recovery than expected.
GST revenue also continued to fall below forecast, by $190 million (4.2%), a significantly lower shortfall than recorded in the three months to September 30, Treasury deputy secretary Colin Lynch said.
"Overall, an underlying weakness remains in private consumption, with households exercising greater-than-expected spending constraint," he said.
However, when compared with the previous corresponding period, tax revenue in 2010 was up 8.9% on 2009.
Government expenses in the 2010 period were $22.1 billion, down 2% on forecast but up 6.2% on 2009.
Asked if Treasury forecasts were again becoming inaccurate, Mr Ebert said the problem came from Treasury forecasting in the May Budget "quite strong growth" for the third quarter, rather than "strong growth".
"It built in a pre-GST spend which didn't happen. The hurdle was always going to be high to meet that forecast."
There might be some post-GST growth in the fourth quarter, but the numbers would be artificial, he said.
The underlying pace of economic growth was disappointing.
While next year would be helped by such things as building activity associated with the Canterbury earthquake, the Rugby World Cup and inventory replenishment, 2012 would show continuing slow growth.
"Next year has the potential to surprise people but they will be one-off factors exciting people. The next three to five years will see relatively low growth rates."
Treasury was likely to revisit its growth forecasts in its December half-year update due on December 14 and the Reserve Bank could acknowledge on Thursday that growth to date had disappointed, Mr Ebert said.
Finance Minister Bill English said the larger-than-forecast deficits reinforced the need for tight fiscal discipline alongside the Government's ongoing efforts to move resources to frontline services.
"While the Government's books had taken a hit from the effects of lower consumption and increased household saving, this trend creates a strong platform for faster growth in the medium and longer term as we rebalance the economy towards savings, productive investment and exports."
That reinforced the need for sound financial management and ongoing discipline in Government spending if the Government was to get back to surplus by 2016, he said.
In the new year, the Government would consider further decisions around how to increase efficiency in the public sector and how it managed some of its large and growing expenses.
That would be assisted by the report of the Welfare Working Group, the Government's review of spending on policy and the ongoing response to the Housing Shareholders Advisory group, Mr English said.
