A man has been injured after falling from a temporary grandstand put up at the V8 Supercars track in Hamilton.

The man was a contractor helping to take down the scaffolding on a field near Waikato Stadium when the incident happened about 4pm, said Hamilton Council spokesman Jeff Neems.

A section of the 20m-tall stand, used for the event last month, is understood to have collapsed.

The incident has been reported to the Department of Labour, said Mr Neems.