A powerful 7.1-magnitude earthquake struck in the southern Indian Ocean on Saturday, but there was no warning issued for a tsunami.

According to reports, the tremor struck around 3,100 kilometres southwest of the Australian city of Perth and around 1,000 km from the uninhabited Heard Island and McDonald Islands.

The epicenter of the earthquake was a tectonic plate boundary located along the sea floor of the ocean called the Southeast Indian ridge. It struck 3,929 m or almost four km under sea level.

As of 4:06 am IST, the earthquake's magnitude had reduced to 6.8.

(Credit: INCOIS/ITEWC)

The Indian Tsunami Early Warning Centre (ITEWC), a branch of the Indian National Centre for Ocean Information Services (INCOIS) in a public bulletin said:

"Earthquakes of this size sometimes have small potential to generate tsunamis. However, so far there is no confirmation about the triggering of a tsunami. An investigation is under way to determine if a tsunami has been triggered. ITEWC INCOIS will monitor sea level gauges near epicenter and report if any tsunami wave activity has occurred."

It also went on to add that "this is only a heads-up message to the national/state/local authorities and disaster management offices. No immediate public action is required. This bulletin is being issued as an advice."