Rather than wait and see whether this current government will fulfill its promises, you better get out there and enjoy the gravel roads while you can, – or just get out here anyway 🙂
https://www.stuff.co.nz/auckland/local-news/rodney-times/104985080/funding-to-seal-rodneys-dire-roads
http://www.driven.co.nz/reviews/reviews/government-announces-99-per-cent-rise-in-road-safety-spending/?ref=nzhhome
Just got a ‘Our Rodney’ newsletter in the mail today. Not something I would normally read but the 121 million dollar sealing budget caught my eye. So that’s a quadrupled increase for sealing Rodney Districts (area from Muriwai bottom left to Te Arai Point top right) gravel roads in the next 10 years.

Auckland Transport’s unsealed road hit list. Priority list of sealing unsealed roads.
That’s a big list, it’s also a great reference of where to find gravel in the greater Auckland area. Some of those roads are 10km long or more and it looks like only the top half dozen are going to be sealed in the near future so there’s quite a few good options further down the list.
Some unformed Roads are going to be closed near Tirau, but the article only mentions 1 of them.
https://www.stuff.co.nz/waikato-times/news/south-waikato-news/107539272/Waikato-road-closure-hiccups-get-costly