The road long been susceptible to rock falls and landslides and a 400-metre section between the scout camp and Byarong Park has been closed to traffic since December 2012.

The last stage of the works was completed this month.

Senior geotechnical engineer Peter Tobin said the project included work on the lower embankment, the upper slopes, and the roadway.

‘‘The road itself was constructed many decades ago and used a ‘cut and fill’ technique that was typical back then for mountain pass construction,’’ he said.

‘‘Unfortunately it didn’t really create the support that was needed and over the years the fill started to settle.

‘‘When we started this stage of the project, the road cross fall was sloping about 16 degrees. A normal cross fall is 2 to 3 degrees.’’

Five rows of rock anchors were implanted into the lower embankment, fixing it to the bedrock.

The area was then meshed and the concrete edge was reconstructed. This allowed the road to be widened by another 1.5 metres, improving safety and line of sight for motorists.

‘‘On the upper slope, a weathered sandstone cliff face, the work we did was all about reducing the rock fall hazard,’’ Mr Tobin said.

‘‘We cleared vegetation and loose rocks, installed rock bolts in boulders, applied shotcrete to some areas and built catch fences.

The road will be closed again in October for about two days to allow the placement of the final asphalt road surface and line marking.

“As with almost all road resurfacing or reconstruction, it needs to be left for around six weeks to settle before the final asphalt surface layer is put in place,’’ Mr Tobin said.

Wollongong Lord Mayor Gordon Bradbery inspected the area on Friday and thanked the community for their patience while the work was carried out.

‘‘It’s been one of the most asked questions over the last 18 months – ‘When is Mt Keira Road reopening?’ and I’m thrilled to now be able to give the answer,’’ he said.

‘‘The road provides a good secondary access route in and out of Wollongong, so along with being a popular tourist drive, it also is great benefit to our emergency services, which is particularly important heading into the bushfire season.’’