Sergeant Aaron Nicholson, of Wanaka, recently warned motorists and cyclists of the danger on the popular tourist route linking Wanaka with Glendhu Bay.
He noted the road surface beyond the fog line was "not very wide at the best of times and over the summer the surface has broken up, encroaching into the main roading lane in parts''.
"With high traffic volumes on the road, parking at Roy's Peak car park spilling out on to the roadway, boat trailers and cyclists all trying to share this section of road, we all need to slow down and take special care in this area,'' he said.
Measurements taken by the Otago Daily Times this week showed the distance between the fog line and the centre line is, in places, several centimetres narrower than the wheel track width of some boat trailers using that stretch of road.
The road is the responsibility of the Queenstown Lakes District Council.
Chief engineer Ulrich Glasner said in an email to the ODT parts of the road between Ruby Island Rd and Glendhu Bay would be widened.
"We have commissioned MWH to do the design work and that is under way. $250,000 has been allocated for that this year.''
Mr Glasner said the council had spent $50,000 maintaining the unsealed parts of Mt Aspiring Rd and $18,000 on the sealed stretch since last July 1.
"That includes fords and crossings, culverts, levelling, fixing edge breaks and marker posts.
"It does not include grading, pothole repairs, spraying and signs. These are all covered under area-wide contracts and we don't break out the figures for what's spent on a particular road.''
Last year the council spent $115,000 on the general maintenance of the road.
Asked if any consideration was being given to reducing the 100kmh speed limit on Mt Aspiring Rd, Mr Glasner said the New Zealand Transport Agency "is considering that at the moment''.
