The Natural Resources Access Regulator is investigating an allegation of illegal water usage in the Gloucester area.
A spokeswoman confirmed the regulator had received a report about a potential breach of water law relating to the Gloucester River.
"Natural Resources Access Regulator staff will contact key persons of interest throughout the investigation, and at its completion to inform them of our findings and our regulatory response to this matter," she said.
"As the investigation is ongoing, we are unable to provide further comment at this time."
Cease-to-pump conditions for the river's water sharing plan have been in place since November 2019.
The spokeswoman said properties with river frontage can pump for a number of legitimate reasons.
"While basic landholder rights apply under the Water ManagementAct 2000 for stock and domestic use, any use of water from the Gloucester River for irrigation purposes requires appropriate water access licences and approvals," she said.
"Water users are expected to know their conditions and comply with them and to check that there are no restrictions in place before they start pumping."
"With extreme drought and bushfire conditions impacting communities across NSW, it is more important that ever that Natural Resources Access Regulator delivers a fair, transparent and effective water compliance system aimed at preventing unlawful water take and improving voluntary compliance."