A diesel spill at Thredbo on Saturday, that leaked into the Thredbo River, has been contained, Andrew Logan, acting manager for the resort section of National Parks, has said.

The spill occurred on Saturday morning and is believed to have happened when the cut-out valve between the main diesel tank and a header tank, at the Valley Terminal failed, causing the diesel to overflow although Mr Logan was not able to confirm these details.

Mr Logan said: "On Saturday morning we were advised by Thredbo that there had been a diesel spill in the village and that both the EPA (Environmental Protection Agency) and the fire brigade had been contacted to assist with containment."

Mr Logan added: "It's a concern when anything gets into the river. It came from a stormwater pipe near the Valley Terminal. The fire brigade have deployed a number of booms on the Thredbo River, several of those are down river, and anything captured has been taken off."

Mr Logan confirmed that there was ongoing monitoring of the water quality and said that there would be an investigation which would take several months.

He was unable to confirm or deny that between 500 and 1,000 litres of diesel had been spilt.

"The booms will stay in place until there is no sign of diesel. It's early days and the initial focus has been on the clean up," Mr Logan said.

Snowy Hydro confirmed that it was aware of the spill and David Hogan said that "some of our guys got a call to go out".

Gnai Ahamet, head of water at Snowy River Shire Council said that she had not received any information regarding the spill.

The Thredbo River feeds into the Jindabyne Dam which supplies Jindabyne's drinking water.