NZ diesel costs about NZ$1.80-2.10 per litre in mid-2026, and petrol about NZ$2.60-2.90. That makes diesel look cheap until you remember Road User Charges (RUC) — a per-kilometre tax on diesel vehicles that's bundled into most motorhome rental rates. For travellers, what matters is what the depot quotes as the all-in fuel cost: most major fleets include RUC in the daily rate, which means you pay diesel pump prices only and the calculation is straightforward.
Diesel — the default for NZ motorhomes
Every 4-berth and 6-berth NZ rental motorhome is diesel — usually a Fiat Ducato or Mercedes Sprinter chassis. 2-berth motorhomes are almost all diesel too. The torque suits the weight of a motorhome on hill climbs, and the economy is 25-35% better than a petrol equivalent at the same load. Real-world economy: 10-13 L/100km for a 2-berth, 12-15 for a 4-berth, 14-17 for a 6-berth.
Petrol — only small campervans
Petrol motorhomes are mostly small campervans on Toyota Hiace or similar van chassis at the budget end of the market. They're fine for two adults on a 5-10 day trip, but the fuel cost over a longer route adds up — a petrol 2-berth doing 12 L/100km of petrol at NZ$2.75 is NZ$33 per 100 km, versus a diesel 2-berth doing 11 L/100km of diesel at NZ$1.95 which is NZ$21.50 per 100 km. Over 2,400 km that's an NZ$275 difference.
Confirm RUC inclusion before signing
If RUC is included in the daily rate (the most common arrangement), you pay diesel pump prices at the bowser — about NZ$1.95-2.05 per litre. If RUC is excluded, you pay pump prices plus roughly NZ$0.85-1.00 per litre equivalent in RUC at drop-off, calculated from the odometer reading. The quote should make this explicit — if it doesn't, ask.