Massive boulders buried in a bank on a major roadworks site in Whangarei have slowed project progress but officials hope the work will be completed in the next few weeks.

The road works on Western Hills Dr has caused rush-hour chaos for commuters over the last few months as work is being completed on a State Highway One roundabout, and the nearby SH1/Manse St intersection.

And it seems the discovery of massive boulders could have slowed the work.

New Zealand Transport Association Northland Highway manager Brett Gliddon said ground conditions on the Kensington to Manse upgrade had been challenging because of a significant number of large boulders, which formed part of the geology in the southern section of the project area where a large retaining wall was being built.


"The ground is made up of dozens of boulders in varying sizes, with an average size of around 27cu m," Mr Gliddon said.

"As a result, extreme care is needed to remove them to ensure the ground conditions remain stable and to protect the safety of both the construction team and those living in the homes nearby."

He said that work had taken some extra time and had affected the completion date.
Some of the boulders will be returned to the area and incorporated into the urban design of the project.

Mr Gliddon said the final stage of the project, which involved completion of the road surface, was planned to take place over Anzac weekend.

And motorists will be glad to hear the landscaping work will continue after this but not affect road users.