A draft Inland Revenue briefing supports lifting the GST rate if required - and notes tax credits could help people on lower incomes.
The IRD briefing also brought up the lack of a capital gains tax, but did not endorse any specific view on it.
Tax expert Geof Nightingale told Heather du Plessis-Allan that lifting GST is a fast and efficient way to raise revenue.
But he says while quick, it's much harder on lower-income people.

Gavin Grey: UK correspondent on Labour's poor showing at the local elections
03:41

Geoff Bertram: energy economist on the Greens calling for the Government to bring down power prices
05:43

Shane Solly: Harbour Asset Management expert on the market reactions to the 'no deal' announcement on the Middle East conflict
03:07