Dualling of a 9.5km between Luncarty and Pass of Birnam will be the second works contract to be awarded on the massive project.

Shortlisted bidders include Balfour Beatty Civil Engineering, Dragados and two joint ventures Farrans Construction and Roadbridge and Wills Bros. Civil Engineering and Lagan Construction Group.

The project will involve four new overbridges to maintain local acess across the A9, along with the widening of one existing underbridge and the provision of a new side road bridge.

Other structures, such as retaining walls and culverts will also be required.

The £3bn project to dual 80 miles of the A9 between Perth and Inverness has been split into 11 contracts which are timetabled to be all completed by 2025.

A joint venture between Wills Bros Civil Engineering and John Paul Construction won the first £35m section from Kincraig to Dalraddy.

Scotland’s Cabinet Secretary for Economy Keith Brown said: “Work on the A9 Dualling Programme is continuing at pace, with preferred routes having been identified for more than 90 per cent of the programme, and we expect to award the contract for the Luncarty to Pass of Birnam section in the first half of 2018.

“The A9 dualling programme is already delivering for our economy by supporting nearly 1,200 engineering-related jobs with many more in the pipeline.”