The incident happened on Tuesday morning at Wombarra, where a developer had closed the southbound lane to allow trucks access to a development for a concrete pour during peak hour.

A motorist who was caught up in the traffic jam said the unapproved closure affected more than just the southbound lane.

“The northbound lane was intermittently blocked as trucks moved in and out,” Ann Chatterly said.

“The traffic back-up was over 200 metres that could be seen by this motorist, with at least a 20-minute delay.”

Ms Chatterly contacted both Wollongong City Council and Roads and Maritime Services (RMS) to report the issue and find out where responsibility lay.

A council spokeswoman said they were aware of the complaint.

“While council is the consent authority for development applications, it is the responsibility of the contractor to ensure they have the appropriate consents to undertake works on roads managed by RMS,” the spokeswoman said.

This is because RMS is the body that has responsibility for Lawrence Hargrave Drive, which along with the M1 Princes Motorway, is the detour route for all traffic during the Bulli Pass closure.

To that end, RMS has moved to ensure no roadwork took place on Lawrence Hargrave Drive over the next two months to limit effects on traffic.

A spokesman for RMS said the concrete pour carried out on Tuesday morning was done “without approval”.

“A Roads and Maritime Services traffic officer carrying out routine patrols immediately stopped the work to ensure all lanes of Lawrence Hargrave Drive remained open,” the spokesman said.

“The developers were informed they could apply for a permit to carry out the work in December, after the reopening of Bulli Pass.”

It is understood that no further action was taken against the developer.