One person has died after a single vehicle crash on State Highway 8, Tekapo.
A second person has moderate injuries.
Police were called to the scene at 3.17pm.
State Highway 8/Fairlie-Tekapo Road was closed while the Serious Crash Unit were at the scene.
Two people have also died after a serious crash on an off-roading track in Mount Richmond Forest Park, Nelson.
The single vehicle crash was reported to police at about 11pm on Monday night.
The two people died at the scene and police enquiries into the crash were ongoing.