Fergus Ewing said it is his and the SNP’s “shame” that it has failed in its commitment to dual the A9.
The SNP MSP for Inverness and Nairn said First Minister Humza Yousaf must now deliver the promise or resign.
Calling the failure “a matter of life and death”, he made a fresh demand for a revised timetable for completing the work.
The comments were made during an A9 crisis summit, hosted by the Inverness Courier at Eden Court in the Highland capital.
Mr Ewing said: “This work must be completed. I was delighted when my government was elected in 2007 and very quickly made a commitment to it.
“To my shame, we haven’t made enough progress.”
However, transport secretary Mairi McAllan said she was not in a position to offer a new timetable.
Instead, it will not be announced until after the Scottish Parliament returns from summer recess on September 3.
A9 dualling: What happens next?
Mr Ewing also asked for changes to the contracts for civil engineering firms to make them more appealing and for evidence that the political will is still there.
Earlier, the summit heard from A9 dualling campaigner Laura Hansler.
The Kincraig resident described the devastation left behind by accidents on the road.
Ms McAllan said she was fully aware that the route is not fit for purpose.
But a “huge amount of work is happening behind the scenes”.
She said: “I want to offer my sincere, heartfelt condolences to every person who has suffered from loss on the A9.
“I had a knot in my stomach when those experiences were being described.
“I myself or when with my family have often had my heart in my mouth while emerging from some of the junctions on this route.”
‘Innocent people have lost their lives’
Mr Ewing was not impressed with the minister’s failure to make a new commitment.
Speaking afterwards, he said he was grateful Ms McAllan had made the trip.
But she left without giving clear answers and “failed on three fronts”.
Mr Ewing said: “The minister failed to deliver a new completion date for the A9 following the failed government promise of 2025.
“She failed to confirm a schedule, and failed to confirm the ‘cast iron guarantee’ that money for the project would not be syphoned off to the central belt.
“There were no commitments from the minister on the A9, and therefore the first minister – who made these commitments – must deliver or resign.”
A9 campaigner Ms Hansler described a situation where a family discovered their loved one had died after seeing a picture of the wreckage of their vehicle on Facebook.
She said: “We’re all very aware of the sirens in Kincraig. You’re left thinking ‘is my partner home? Is my son home?’
“Innocent people have lost their lives and we need solid action to take this forward.”
‘The promise was made, but not a lot of work was done behind it’
Earlier, the summit heard from Grahame Barn, chief executive of the Civil Engineering Contractors Association.
Mr Barn said the A9 dualling promise fell down the list of priorities for the Scottish Government.
He also described how the terms on offer to contractors were not appealing.
Mr Barn said: “When the promise was made it was achievable in the timescale they gave themselves.
“But they needed to have a plan. And they needed to have the money there to have a rolling programme of bringing out sections to be tendered for and then built.
“That’s the problem. The promise was made and then not a lot of work was done behind that to deliver on it.”
The Scottish Government committed to dualling the A9 between Inverness and Perth in 2011.
But in February, then transport minister Jenny Gilruth admitted the completion date was “simply no longer achievable”.
On Tuesday, Transport Scotland confirmed a new timetable will be revealed in the autumn.
