National's promising to stick to three spending guardrails if it returns to Government, and is calling on other parties to follow suit. 

The party's promising a return to surplus in 2028/29  - and bending debt below 40 percent of GDP. 

It's also promising to reduce the size of Government, bringing spending to 30 percent of GDP. 

Finance Minister Nicola Willis joined the Weekend Collective to explain further.

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