Fuel manufacturing costs have fallen by more than half in the last four years, reducing prices for consumers.

The petroleum and coal product manufacturing industry makes things like petrol, diesel and aviation fuel.

The ongoing global downturn in crude oil prices has been influencing costs for the sector in New Zealand.

Input and output costs for the industry fell about 20% in the last quarter.

That's having a flow-on effect for transport and construction, and ultimately households.

Petrol prices have fallen 7.7%, as measured by the consumers price index.