The blaze had started in the venue seats and taken almost two hours to extinguish but no casualties were reported.

A spokesman for the fire brigade said: "PVC sheet was being laid when the fire broke out due to carelessness in welding work."

He said the fire was put out within two hours.

After the fire was reported at the under construction Rugby stadium around 7 pm, six fire engines were rushed to the spot, officials said.

The fire brigade spokesman said: "The fire was put out by around 9.15 pm.

"Cause of the fire is yet to be ascertained."

The extent of the damage was not immediately known.

The site was cordoned off by private security guards deployed by Gammon India, which is constructing the stadium.

The under-construction stadium at Hindu College in Delhi University will host rugby sevens matches during the Games, which are due to begin on October 3, 2010.