A motion has been lodged in the Scottish parliament highlighting the “substantial discrepancy” between isles fuel prices and those in mainland Scotland.
The motion highlights recent drops in crude oil prices, but insists pump prices in Shetland and Orkney have failed to reflect the decrease.
Diesel is said to cost up to £1.44 a litre in the isles, compared with some mainland prices of just £1.19.
The motion, lodged by Shetland MSP Tavish Scott and his Orkney colleague Liam McArthur, comes six years after a UK government scheme to cut fuel duty in rural areas was introduced.
However, it argues that further “sustained action” is required to cut the cost of filling up at the pumps.