Unsealed Roads

Central Otago has a one of the largest unsealed road networks in New Zealand, with 74% of the roading network unsealed.



Grading frequency for each road is set depending on the hierarchy classification of the road, with the busiest roads graded more often. 

​Hierarchy​Base grading
​Major​8 grades per annum
​Intermediate​4 grades per annum
​Minor​3 grades per annum
​Lane​2 grades per annum
​Track​1 grade every 15 months

Some roads are graded more frequently than this due to the topography or traffic volumes on the road.

There are three different grading areas, and each year a plan is prepared for each area. The plan takes into account the number of times each road should be graded and when the grader will be within the area.

The grading plan is subject to change depending on weather and road condition, and other activities on the network such as events.




Over time unsealed roads experience gravel loss and re-gravelling is required to restore a suitable driving surface.

A list of roads that require gravelling is prepared every three years. There are more roads that require gravelling than there is funding available to do. The list of road for gravelling has to be prioritised to keep within the available funding.

The priority is set based on the hierarchy classification of the road, the condition of the road, and consideration of safety and accessibility issues.


Sealing Unsealed Roads

Council does not currently have any funding set aside in the 10-year plan for sealing unsealed roads.


Dust Suppression

Eco sealing

Since 2008 Council has been applying eco seal to 100m sections of gravel roads where there is a house located within 100m of a gravel road as a dust suppressant.

Eco seal is a low cost type of seal which is more environmentally friendly and lasts longer than oil. Eco seals are applied to a 100m length of road when the road is re-gravelled.


Applying oil to gravel roads as a dust suppressant is being phased our due to its environmental impact and cost. Council will still apply oil to a 100m length of road where there is a house within 100m of the gravel road until eco sealing is undertaken.

Otago Regional Council rules require the oil which is applied to roads is to meet certain standards. For this reason Council tests the oil and it may only be applied by our Contractor.

Please contact Council if you require oil to be applied to a gravel road.

Page reviewed: 21 Jul 2015 11:01am