The corporate tax take appeared to be due to higher-than-expected corporate profitability, but gross domestic product in the third quarter was lower than the Prefu forecast, suggesting profitability might be lower than forecast by year's end.
"So overall, there is a downside risk to tax revenue for the current year," Welsh said.
The cash deficit for the five months to November was $7.5 billion, $280 million bigger than forecast.
Finance Minister Bill English said the revenue shortfall reinforced the need for ongoing spending restraint and responsible fiscal management.
"The Government is committed to ... returning to surplus in 2014/15," he said.
Returning to surplus and repaying debt were among the most important things the Government could do to ensure New Zealand could withstand future shocks and build a more competitive economy.
English said the Budget Policy Statement on February 16 would confirm the Government remained on track to post a surplus in 2014/15.