The rock art site has been enhanced by Ngai Tahu's Maori Rock Art Charitable Trust and is attracting more tourists, who park in lay-bys on both sides of the road.
However, the proximity of parked cars and people crossing the road to a bend in the highway has raised issues about safety standards.
The New Zealand Transport Agency (NZTA) now plans to do something about it.
It has issued a requirement to the Waitaki District Council to designate land as part of the state highway so a car park and picnic area can be constructed on farm land about 70m west of the site.
Turn areas would be provided off SH83 into the car park.
In its requirement notice to the council, the NZTA said the car park would allow for safer access to the Maori rock art site, located in a more central position between two bends for improved visibility.
The sealed car park would have room for 12 light vehicles and a bus.
There would be a landscaped picnic area with tables and rubbish bins.
A track from the car park to the rock art site would provide access.
It would take about 10 weeks to build the car park and alter the highway.
The NZTA said the rock art site was a significant attraction, with between 20,000 and 30,000 people visiting a year.
But visibility was restricted on the highway by two bends and a World War 1 memorial oak.
"As visitor numbers, traffic volumes and vehicle speeds have grown over time there has been a corresponding increase in concerns about visitor safety," the NZTA said.
The car park would give vehicles and pedestrians safe access to the rock art site.
One issue raised by the Maori rock art trust was the "high potential" for archaeological sites to be disturbed during construction.
There are five sites of significance within 500m.
The NZTA will need an authority from the Historic Places Trust, and if any archaeological material is disturbed, work will cease and the trust, Maori representatives and an archaeologist will be contacted.
