Formally, the central bank is hamstrung on such things as it has to defer to announced government policy.
The official cash rate is expected to stay at 2.5% today.
However, Bank of New Zealand senior economist Craig Ebert said the Government itself had been sounding the high likelihood of the Budget doing such things as abolishing depreciation allowances on property investments, increasing GST to 15% as early as October 1 while reducing the top personal tax rate to 33% from 38%.
"The net result will probably be a stimulative Budget, especially for the potential to boost spending for the very near term.
"This would include the potential for new home-building activity and sales to rush to beat any rise in GST, for which it is liable."
The presumed rise in GST would overlap with several other one-off measures directly affecting the consumer price index - the official measure of inflation, he said.
Examples were the July 1 introduction of the Emissions Trading Scheme, which would increase fuel and electricity prices, and the higher ACC charges implemented to better fund the Government's insurance scheme.
All of that had the potential to push annual inflation above 4% by the end of the year, Mr Ebert said.
"We know the Reserve Bank will look through these spikes as best it can and it can probably do so with some comfort in that core price pressure is likely to be relatively muted this year.
"Still, consumer price inflation running above 4% could prove nettlesome for the Reserve Bank if it coincides with surging GDP growth."
None of the indicated Budget changes would be in the Reserve Bank's policy statement projections today.
But they should certainly be in its thoughts and profiles, Mr Ebert said.
Other than that, Mr Ebert was expecting the key policy signal from the statement to come through the central bank's forecasts of the 90-day bank bill yields.
He was expecting those to be essentially unaltered from that portrayed in the December statement.
That would imply a first official cash rate rise about the middle of the year.
"All things considered, we will prefer June as the start-point to OCR hikes - a view we've had on the board for quite some time now," he said.
