The State Emergency Service's contact phone line went down Thursday evening, the organisation has said.
Technicians were working to resolve the issue around 8.20pm, as storms and heavy showers rolled over Newcastle and the Hunter.
A trough settled across western and southern parts of the state, mingled with a blanket of humid air, was expected to bring rain and thunderstorms to the region over the coming days, as flood waters in the Upper Hunter continue to recede.
NSW SES has advised that in a life-threatening situation, residents should contact Triple Zero (000), while technical issues with the service's phone lines were being addressed.
NSW SES is expected to provide an update when the phone line has been restored.
