Two people have died in a massive earthquake which struck off Indonesia, destroying buildings and triggering a tsunami.

Geoscience Australia reports the quake measured at a 7.7 magnitude and hit about 20km underground just off the north coast of Flores island about 5am on Saturday.

WATCH THE VIDEO ABOVE: Earthquake severely damages port terminal in Indonesia

The island is home to a number of popular tourist destinations, with the undersea earthquake hitting near the city of Maumere.

It was followed by several aftershocks — measuring up to a 6.2 magnitude — across the coastline in the hours after the initial quake.

Footage geolocated by 7NEWS.com.au shows people running for their lives as huge chunks of debris fell off a building at a port in Maumere.

Two confirmed dead in quake

The falling debris killed two people and struck hundreds of others waiting to board a passenger ship, Maumere Search and Rescue (SAR) Chief Fathur Rahman said.

“One person died at the hospital after being evacuated and the other was found dead amidst the building’s rubble,” he said.

The country’s Disaster Countermeasure Agency confirmed the first known victims of the disaster were a man and a woman.

“Once the data are confirmed, we will officially announce the final number of casualties and the extent of damage to buildings caused by the earthquake,” agency spokesman Berton Suar Pelita Panjaitan told reporters.

That total is expected to rise as the US Geological Survey suggests about 500,000 people were exposed to very strong or severe shaking, which is capable of slight to moderate damage in well-built structures and great damage in poorly built structures.

Other images and videos shared to social media, which are yet to be verified, also show several buildings across the region had been damaged in the earthquake.

Tsunami warning issued

Indonesia’s geophysics agency BMKG issued a tsunami warning for some regions of the country.

Locals in coastal towns across the East Nusa Tenggara and South Sulawesi regions were urged to “immediately guide their communities for evacuation”.

The country’s Meteorology, Climatology and Geophysics Agency confirmed a “tsunami was generated” but has since passed.

“The expected period of significant tsunami waves is now over,” the agency said.

However, it also warned that “dangerous currents can continue for several hours after the main tsunami waves have passed”.

⁠Australia’s tsunami warning centre said the quake will have “no ​tsunami ⁠threat to the Australian mainland, islands or territories”.

Latest earthquake to rock the nation

Indonesia has seen several devastating earthquakes in the past. The country sits on the Ring of Fire, a band around the Pacific Ocean that sets off frequent earthquakes and volcanic activity.

The ring is one of the most seismically active areas in the world, spanning from Japan and Indonesia on one side of the Pacific to California and South America on the other.

The catastrophic Indian Ocean tsunami of 2004 was sparked when Indonesia’s Sumatra island was hit by a quake with a magnitude of 9.1.

The resulting disaster killed more than 220,000 people along the ocean’s coasts, more than half of them in Indonesia.

More recently, hundreds were killed when a 6.9 earthquake hit the island of Lombok in August of 2018. Later that month a trio of intense earthquakes shook several islands in the South Pacific and Indonesia.

More to come ...