Oreti Beach near Invercargill. Photo: ODT/File

A child is seriously injured after crashing into a stump on a quadbike on Invercargill's Oreti Beach on Saturday afternoon. 

A police spokesman said the incident happened about 12.45pm. 

A St john spokesperson said they assessed, treated and transported one patient in a serious condition to Southland Hospital. 

Oreti Beach is one of only two beaches in New Zealand that vehicles are allowed to drive on.