Four people have been injured, including one seriously, after a jet boat flipped on the Rakaia River.

Emergency services were called to the scene shortly after 7pm on Saturday.

A police spokeswoman told chrislynchmedia.com that a tractor was used to right the overturned jet boat.

A St John spokeswoman said three helicopters were dispatched to the site.

“Crews assessed and treated four patients—three in moderate condition and one in serious condition—all of whom were airlifted to Christchurch Hospital,” she said.