POLICE have made an arrest in relation to a lockdown at a Northern Rivers school on Tuesday.

A NSW Police spokeswoman confirmed that officers from Richmond Police District had charged a man over the incident.

"In relation to the school, a 27-year-old man has been charged with three counts of use carriage service to threaten serious harm," she said.

"He was granted conditional bail to appear at Lismore Local Court on November 23."

On Tuesday shortly after 12.10pm, police were called to Wyrallah Rd Public School following reports that "verbal threats" were being made.

Residents in streets near the school reported hearing a repeated announcement about the lockdown over the school's loudspeaker.

"The school voluntarily went into lockdown before officers attended and conducted a search of the premises, with nil find," a police spokeswoman said.

Around 1pm yesterday Wyrallah Public School posted on social media limited details of the incident.

"Today we had a precautionary lock down commencing at 12.10pm," the post read.

"All students and staff are safe. The lockdown ended at 12.50pm. "

The NSW Department of Education has been contacted for comment.