Police remained tight-lipped yesterday on the circumstances surrounding the alleged incident, which was understood to have happened about 10pm.
While a police spokeswoman confirmed the cordon near the South Canterbury township was lifted shortly after 2pm, police were ''still making inquiries to understand the circumstances of the incident''.
Earlier, Sergeant Blair Wilkinson, of Oamaru, told the Otago Daily Times police from Oamaru and Waimate converged on the scene on the northern side of the Waitaki River bridge after at least three gunshots were heard.
Sgt Wilkinson confirmed the incident was being investigated by the Timaru CIB.
Two armed police were guarding the scene about 9.40am yesterday, while at least two other officers carried out a scene examination which had since been completed.
A small area directly opposite the rest area was also cordoned off.
Inquiries were continuing and no suspects were being sought at this stage.