A landmark road which played a key role in the Central Otago gold rushes has been recognised by the New Zealand Historic Places Trust.

The Old Dunstan Road was the main route for gold prospectors travelling to the Dunstan goldfields in the 1860s.

It is 120km long and covers four mountain ranges.

NZHPT Southland area manager Owen Graham said today the road was added to the trust's national register because it was of outstanding heritage and historic significance.

"It is one of the country's longest and oldest heritage roads and has remained in a largely original state nearly 150 years after its formation by the earliest pastoralists," Mr Graham said.

"It is still well used today for farming and local purposes and increasingly tourists are travelling the road to view the dramatic and beautiful natural and historic setting the road passes through."

NZHPT hoped that with co-operation from local councils, appropriate signage, including interpretation panels for visitors, could be erected at key locations along the road, Mr Graham said.