The new Scottish government has described plans for dualling the A9 road as a "long-term" project.
The SNP administration is looking into the issue, but stressed there was no intention to divert funding from public transport projects in Edinburgh.
It has raised concern about the city's tram and airport link projects.
Making improvements to the A9 was a commitment in the SNP 2007 election manifesto, along with similar plans for the A96 and A77.
An official spokesman for First Minister Alex Salmond described the timescale for the A9, which is known for its accident blackspots, as "long-term", but declined to be drawn further.
The spokesman said: "Long-term is long-term. It is not an immediate priority."
There have been long-standing calls to dual the A9 between Perth and Inverness.
The Edinburgh projects and other longer-term plans, the spokesman said, were funded from different budgets.
The spokesman said: "The government is considering the robustness of the financial case for the Edinburgh Airport Rail Link and the Edinburgh trams projects, where there are significant concerns about the ability to deliver these and about the costs involved."
"The government intends all expenditure planned for these projects or any alterations will continue to be used for public transport projects that tackle congestion, connectivity and journey times in Edinburgh and across Scotland."