Environment Southland says it can't proceed with a request to review consent for a major data centre.

Development of the $5 billion Datagrid AI factory is underway at the Makarewa site, with consents to draw up to 600,000 litres of groundwater a day.

Datagrid has since said it cut its expected water use by 70 percent, and the centre would run primarily on rain water.

Southland Sustainable Resource Coalition requested Environment Southland review Datagrid's consent for water take and use.

Environment Southland general manager strategy & regulation Hayley Fitchett said a consent may be reviewed in certain circumstances, including where it was necessary to ensure limits set in a regional plan could be met.

"In this case, the company's consented operational water take is less than 10 percent of the limit set in the Proposed Southland Water and Land Plan."

Environment Southland's resource consents relate to discharges to air and land, taking water, and a small wetland.

Fitchett said Datagrid's resource application was not publicly notified because it was assessed as having only minor environmental effects, as defined in the Resource Management Act.