Police are investigating possible sabotage at the Bathurst racetrack ahead of its meeting on Friday.
The irrigation system was activated sometime overnight with a section of the track from the 800 to the 700 metres waterlogged.
Racing NSW's chief steward for the region, Todd Smith, confirmed police had attended the course to follow up reports the irrigation system had been manually activated overnight, water tanks and pumps for the stabling area were disconnected and some equipment taken from the irrigation pump shed.
Racing NSW chief executive Peter V'landys said the club had begun stepping up security and installing CCTV cameras.
The final race on the eight-race program was called off when the affected section became too damaged.
Earlier this year, the club had its licence suspended when the track was over-watered but was later given the go-ahead to operate again.