KiwiRail have dismissed corruption allegations following an independent investigation into infrastructure contract irregularities.
The independent investigation into the irregularities found no evidence to support the claims, KiwiRail says.
The company's chief executive, Jim Quinn said KiwiRail commissioned the investigation by PricewaterhouseCoopers (PwC) immediately after receiving anonymous allegations asserting issues with some infrastructure contracts.
"Pleasingly and as expected, their investigation found no evidence to support the allegations."
The report was also given to the Serious Fraud Office, which has said there was no evidence to support opening an investigation, Mr Quinn said.