Transport Scotland have confirmed the Aberdeen bypass will not be fully open in time for Christmas.
The final 4.5 mile stretch, between Parkhill and Craibstone, had planned to open before December 25.
However, Aberdeen Roads Limited have confirmed the deadline they confirmed during a meeting with ministers will be missed.
Instead the firm are targetting a January 2019 completion, although no definitive date has been confirmed.
The last section of road has been delayed by works on the new River Don crossing.
Keep up to date with the latest news with The Evening Express newsletter
Transport Secretary Michael Matheson said: “This week, ARL informed us it was no longer able to meet its own deadline of concluding works at the Don Crossing before Christmas.
“This is just over a fortnight since it set this deadline publicly in Parliament.
“I have consistently urged caution and realism about ARL’s ambitious timescales.
“Unfortunately, as disappointing as this news is, it comes as no surprise to me it has been unable to achieve this.
“We have been here before with ARL.
“My officials and I will continue to work constructively and offer every assistance to get the remaining 4.5 miles open as soon as possible.
“I also want to pay tribute to the workforce who have undoubtedly been working hard during this most challenging time of year.
“It is well known that ARL has experienced a series of technical issues during the construction of the Don Crossing.
“In order for this Government to protect the public purse, it is imperative that ARL provides the necessary technical and commercial assurances for the Don Crossing.
“We cannot and will not contemplate releasing payments for this structure without these critical assurances.”
Mr Matheson added: “More than 85% of the AWPR is now open to traffic and is delivering immediate benefits which the people of the north-east are clearly enjoying.
“I’m thrilled to be seeing story after story of people and businesses seeing substantial improvements to their journey times and reduced congestion across the city.
“Obviously this is still anecdotal but the road has been performing very well so far.
“It has been a very vivid demonstration of the transformation that infrastructure can bring about in people’s daily lives, the quality of their environment and the economy as a whole.”