Toyota iQ gets more power
At present, the iQ is only available with a 67bhp 1.0-litre engine that averages 65.7mpg and emits 99g/km of carbon dioxide.
The new 1.33-litre unit will be added to the line-up from June.
It has 98bhp and averages 59mpg, while emitting 113g/km of CO2 with the six-speed manual gearbox.
The optional automatic Multidrive gearbox lowers the car to 57mpg and raises emissions to 120g/km.
Prices will be released nearer the on-sale date.