Small quake hits NSW mid-north coast

A map of the earthquake location east of Seal Rocks, New South Wales, from Geoscience Australia.

Geoscience Australia

PARTS of eastern NSW have been shaken by an earthquake off the state's mid-north coast.

The minor, 3.4 magnitude, quake struck at 3.25am (AEDT) on Friday, 80km east of Forster, Geoscience Australia told AAP.

Geoscience Australia senior seismologist Dr David Jepsen said Friday's quake was very minor, but felt as far away as Newcastle and north of Forster.

Residents reported feeling a rumble lasting a few seconds, while others heard it, he said.

Candice Neat, a resident of Hawks Nest, south of Seal Rocks, said she was woken up by the quake.

"We were rocking in our beds and the windows were shaking," she told the Seven Network's Sunrise program.

"It was a bit scary, we didn't know what was happening."

Her house was not damaged.

The quake might have gone unnoticed if it had happened during the day.

"When people are quiet and lying down they are more sensitive," Dr Jepsen said.

"To put the event into perspective, earthquakes with magnitude 3.4 and above occur around the world about 100 times per day on average.

"It's small and one of many.

"For its size, we wouldn't expect much damage."

The State Emergency Service (SES) said there had been no reports of damage or calls for help by about 7am (AEDT).

No tsunami warning had been issued, the SES told AAP.

Almost exactly one year ago, a similar small quake was recorded off Ulladulla on the NSW south coast.

The last notable quake in the Seal Rocks area was in June 1916, when a 4.5-magnitude tremor damaged the town's lighthouse and was felt as far away as Sydney.

Compared with the 8.8-magnitude Chilean quake of February 27, the latest one off NSW released about 30 million times less energy.

Australia records an average of more than 30 earthquakes of similar magnitude each year, Dr Jepsen said.