Treasury says the government's corporate tax take may miss forecasts for the rest of the financial year, leaving the Crown vulnerable to a bigger-than-expected annual deficit.
The government's tax revenue was 2.9 percent short of forecast at $31.36 billion in the seven months ended Jan. 31.
The Treasury said tepid wage growth and employment sapped source deductions, while insurance companies sought GST refunds, and companies paid less tax than forecast.
The operating balance before gains and losses (OBEGAL) was a deficit of $4.31 billion in the period, wider than the shortfall of $3.84 billion flagged in the pre-election economic and fiscal update (PREFU).
"Corporate tax assessments in the month of January were below forecast which is a pattern that is now expected to persist to the end of the financial year," chief financial officer Fergus Welsh said in a statement.