Council are in the final stages of the upgrade, and part of this will involve the testing of the new sirens.

This testing is scheduled to occur next week.

Council said they wanted to advise residents that no action needs to be taken on their behalf.

Once the system is operational, Council, in conjunction with the SES, will be running some informational sessions on what to do if you hear the sirens, along with a general flood awareness campaign.

Tenterfield mayor Peter Petty said he was also excited to inform residents that, as part of this project, the rainfall, creek and dam level information will be made available to the community.

"Further information on how to access this data will be made available when the system is operational," he said.

NSW residents are being warned to batten down the hatches with heavy rain and storms forecast toward the week's end.

Heavy falls have already caused isolated flooding and have soaked catchment areas, particularly in the NSW mid-north and north coast, where more than 600mm of rain has fallen in the past month.

The NSW State Emergency Service has warned saturated catchments means rivers will be quick to rise with an increased risk of flash flooding.

SES volunteers responded to 371 requests for emergency storm and flood assistance across the Northern Rivers, Mid North Coast, Hunter and Central Coast as recent rain fell on already wet catchments.