Residents in towns along the NSW mid-north coast inundated police with calls of a tremor that shook homes on Monday evening.

Taree police said they took "a lot" of calls from people in the area reporting an earth tremor about 9.30pm (AEDT).

But in Canberra, Geoscience Australia, the agency that measures seismic activity, said it had not recorded any tremor in the area.

"We have registered absolutely nothing at all on our seismograph," a spokeswoman said.

Police said they received calls from concerned residents.

"Most of the calls came from Forster, with people saying their windows and doors were rattling," the police spokesman said. "A few residents were concerned people were breaking into their homes. But it's a fair dinkum mystery what happened."

The "tremor" lasted anything from a few seconds to up to two minutes, according to reports.

Taree radio station 2RE announcer Jeremy Miller said he started taking calls about 9.25pm (AEDT) from people wondering what was happening.

"It was felt around Forster, Nabiac, and then up as far as Taree, Wingham.

"The Taree Aquatic Club told me they felt the windows rattle for a couple of minutes."

One caller to 2RE, reported on Macquarie Radio, said: "There was all this shaking; my windows were just shaking."

Another caller said: "Both my doors, back and front, rattled at the same time, it sounded like there was thunder but it wasn't thunder. It was definitely coming from under the ground."