Sydney: Australia's Barrier Reef district was rocked by an earthquake of 5.2-magnitude on Saturday but locals said they barely felt a thing.

According to the United States Geological Survey, the tremor struck about 3.30pm about 124 kilometres southeast of Townsville at a depth of 10 kilometres.

Australia rarely experiences earthquakes, its land mass being some distance from the boundary of the Indo-Australian tectonic plate.

A low rumbling was also felt at Magnetic Island, a 20-minute ferry ride from the mainland and part of the Great Barrier Reef, according to a hotelier at the All Seasons resort.

"Some of the guests felt a bit of a shake, nothing much. It wasn't major, no-one fell over and nothing was damaged," she said.

There were no immediate reports of damage and no tsunami alert was issued.

"Look, we're pretty laid-back around here and it'd take something more than that to shake us up!" a publican at the local Molly Malone's Irish Bar told.