Campaigners have warned that approval for 310 new homes could push a blackspot Mearns junction beyond breaking point.
A decision to give the go-ahead for a major expansion of Laurencekirk without a flyover yet being in place was described as “complete madness”.
Jill Fotheringham, who has led the campaign for a flyover, said the impact on the junction would be “catastrophic”.
She said she could not believe councillors unanimously approved the application despite no concrete Government commitment on the junction at Laurencekirk.
“There is already a development of over 100 houses started in Laurencekirk at the south end of the town,” she said.
If these houses go ahead without the flyover being in place it will be catastrophic.
“I cannot believe after all we have been told and promised that they will start building them. It’s complete madness.
“I am all for development in Laurencekirk but the proper infrastructure must be in place before any of it goes ahead.”
Kirkwood Homes Ltd plan to build 310 houses, including 77 affordable units, at Conveth Mains, Laurencekirk.
Councillors on Kincardine and Mearns area committee unanimously approved the application and work is expected to begin later this year.
The decision was made despite objections to the proposals around the impact on the neighbouring north and south junctions onto the A90 Dundee to Aberdeen road.
Locals have been calling for action at both spots where the A937 Laurencekirk to Marykirk road meets the A90 particularly the south junction for years.
Councillors last year backed building a grade-separated junction at the south junction across the A90 following an 11-year campaign.
However, Transport Scotland, Nestrans and the council are yet to come to an agreement about who will fund it.
Ms Fotheringham has now written to the transport minister asking why it is being allowed to happen.
Committee members said they had little choice but to back the plans, as the site is within the local development plan and the masterplan was approved in 2014.
The council’s own infrastructure service and Transport Scotland had initially objected to the proposals due to the A90 concerns.
Allan Rae, land director for Kirkwood Homes, said they were delighted the development had been approved.
Mearns Community Council had objected to the application.
North East Conservative MSP Alex Johnstone has also hit out at the decision to approve the application before any upgrade to the junction has been started.