This paper examines how pre-tax petrol and diesel prices in New Zealand respond to changes in crude oil prices using an asymmetric error correction model. Our results show that oil companies adjust diesel prices upwards faster than they adjust them downwards, and the difference is statistically significant. However we find no statistical evidence for an asymmetry in the adjustment of petrol prices even though the magnitude of estimated coefficients suggests a faster response to rising prices. As diesel pricing is not as competitive as petrol pricing, calls for further government actions and monitoring of the oil market may be justified. Our findings also have important implications for the conduct of monetary policy as the pass-through of crude oil price changes can affect cost-push inflation.