Motorists in rural areas could see their fuel bills cut by up to 5p a litre under the proposed expansion of a duty discount scheme.
The UK Government has asked the European Commission to consider seven new regions across Scotland and in a part of north-east England.
Chief Treasury Secretary Danny Alexander, a Highlands MP, said: "High fuel prices in areas where cars are a necessity, not a luxury, is a major issue in rural communities across the UK. So, following a supplementary call for information, I'm pleased to announce that seven new areas will join the 10 areas already part of our new application.
"Reaching agreement with the commission will not be easy, but we will now get on with making that case as strongly as we can."
The applications cover postal areas in Strathcarron, Ullapool, Lairg, Mallaig and Halkirk in the Highlands; Oban in Argyll and Bute; and Hexham in Northumberland.
They are added to 10 applications already identified in the Highlands, Argyll, Cumbria, Devon and North Yorkshire.
A final decision is expected from the commission later this year. If approved, it could benefit about 125,000 people, according to the Treasury.