A massive rockslide caused by heavy rain in North Otago has threatened the preservation of a popular ancient Maori rock drawing site.
The huge landslide, which happened overnight, has blocked access to the Takiroa rock art site on State Highway 83 near Duntroon. Potential risk to the artwork is being assessed.
Ngai Tahu Maori Rock Art Trust curator Amanda Symon said the "incredible rain event" experienced in the area had saturated the limestone outcrop, causing a "significant slump".
"Limestone is obviously a porous rock... a lot of water poured on it," she said.
" It's just a shame the weather took it's toll."
Ms Symon said the primary concern was public safety at the site - which is visited by more than 20,000 people each year.
"The condition of the rock art is a secondary concern," she said.
"The piece of rock that has come down is an overhanging piece. The rock art is in the alcove area, under that overhang."
Ms Symon said the area was closed off to the public until it could be assessed.
She believed the art had not been damaged, however, the slip could lead to more exposure.
"The area had been caged for the protection of those treasures. Over the last few years local marae and the Ngai Tahu Maori Rock Art Trust had spent a lot of time, effort and resources in beautifying the site."
The rock face has a number of drawings which date back to the 19th century and appear to depict European style sailing vessels and people riding horses, as well as taniwha, birds and other animals.
Ms Symon said there were at least 580 similar sites around the South Island but very few were accessible to the public.
"There's a lot of art there. It's unusual because there's a profusion of red used... and there's ancient art alongside contact period art."
Ms Symon said the area would remain closed until the weather had cleared, roads had reopened and the site was cleared for safety.