The NSW government has ordered another review of speed limits on Appin Road.
This is despite reviews earlier this year and last year which found the limits were appropriate.
Roads Minister Duncan Gay called for a detailed study of the road in 2012.
Part of that included a review of the speed limits, which change four times from the outskirts of Campbelltown to Bulli Tops.
That review was carried out by Roads and Maritime Services (RMS) in January 2013, and the findings were that all limits were appropriate.
In March 2014, the Centre for Road Safety's detailed study was released saying "the application of speed zoning along the road appears to be consistent".
However, opposition spokesman for the Illawarra Ryan Park recently asked Mr Gay a number of questions without notice on Appin Road, including the possibility of another speed zone review.
Mr Gay replied that another review would take place, focusing largely on the 100km/h sections of the road.
He also said RMS had no plans to widen the road.
A spokeswoman for Mr Gay said this week the new review did not mean there were problems with previous findings that the speed limits were suitable.
"The review of the speed zone now being carried out on Appin Road will take into consideration an additional 15 months of crash data."
The Centre for Road Safety review also highlighted four "crash clusters" along the route - the speed limit is 100km/h at each of those locations.
A reduction in the speed limits - mainly on the single-lane sections of the road - could be on the cards, as a similar move elsewhere on Appin Road proved successful.
In 2002 the speed limit between the Appin township and Campbelltown was dropped from 100km/h to 80km/h, which the RMS said resulted in a significant reduction in fatalities and crashes along that section of road.