Police are asking Southland drivers to take extra care, following six crashes on one stretch of road in the area this year.
Senior Constable Kelvin Templeton said there was ample signage on State Highway 99 between Riverton and Wallacetown, but it appeared people were not registering the signs or were choosing to ignore them.
Mr Templeton said two of the six crashes on the 27km long highway had been fatal.
Last week a 65-year-old man died in a single-vehicle crash on the highway.
Mr Templeton said Southlanders needed to be aware that driving conditions could change regularly, as a result of wet, cold and windy weather in the region.