The carmaker says savings of £500 per year are possible, as LPG's average cost of 58.6p per litre is around half the cost of petrol.
The model is sold already fitted with an LPG conversion, which in the aftermarket would cost almost £2,000.
There is no price premium, as EcoLogic is priced £10,995 as five-door hatch and £10,795 as a four-door saloon, the same as the non-LPG variants on which it is based.
Simon Park from Proton Cars UK said: "Soaring food and utility bills are crippling many families and our dual fuel car provides a genuine solution for long-term savings at the pump.
"Although there are more than 1,400 LPG filling stations in the UK, drivers can opt to fill up with unleaded and switch at any point in their journey thanks to the car’s dual-fuel system."