By Michael Ryan* of

Finance Minister Nicola Willis.

Analysis: As New Zealand's Budget Day looms closer, the government has already revealed one important figure - $2.1 billion - that offers an insight into its approach to spending this year.

That's the government's tight operating allowance - or the new money available for ongoing spending. And that's already been trimmed back from $2.4b since its budget strategy was announced in December.

The $300 million cut is small relative to total operating expenses, but still significant.