If elected the party had committed to adjusting tax brackets to make up for inflation pushing many "middle New Zealanders" into high tax thresholds.
It would also remove the top personal tax rate of 39 per cent.
Both would occur in the first three-year term, with the tax bracket adjustment followed by the abolition of the top rate when fiscal circumstances allowed.
That would, however, be accompanied by "more disciplined government spending, reprioritising projects, cutting out waste, cutting back bureaucracy".
The British government's plan for big spending and big tax reductions at the same time was, by contrast, "economically unorthodox" and would require "massive" borrowing, Willis said.
Yesterday's visit was Willis' first to the Far North since being named deputy leader in November last year. She took on the party's top finance role in March.
It was her second visit to Northland in that time with a trip to Mangawhai in June.
She met supporters at a Kerikeri cafe in the morning, went for a walkabout to meet locals, visited Hospice Mid-Northland, and attended a business lunch at Marsden Estate.
Issues raised by the public during her walkabout included law and order and, inevitably, the state of Northland's roads.
A few days earlier Far Northerners had learned there was a chance State Highway 1 through Mangamuka Gorge, which closed in August, might never reopen.
Willis said she realised that posed "real issues" for the Far North in terms of resilience, connectivity and the economy.
National had not yet announced which roading projects would be prioritised as part of its election manifesto, but she said the party had a track record of investing in good transport infrastructure and the north would get its fair share.
She did not have a view as to whether Mangamuka Gorge should be reopened or an alternative route developed.
"That's one of the issues that I'm going to talk to locals about. I want to get their feedback on that and understand what people want to see prioritised," she said.
Areas, where National planned to cut costs to help pay for tax cuts, included Three Waters reform and subsidies paid out to large multinationals for reducing carbon emissions.
Climate change had to be addressed but big global firms should "do that off their own backs", she said.
• National will open nominations for its next Northland candidate on January 10. So far outgoing Kaipara Mayor Jason Smith and Far North District councillor Felicity Foy have made their intentions public but two others have expressed interest. If more than five people put their hands up, a local pre-selection committee will whittle them down to a shortlist for Northland delegates to choose from. National's last Northland MP, Matt King, lost to Labour's Willow-Jean Prime in 2020 and has since quit the party to set up his own, Democracy NZ.