Albanian rescuers are scouring rubble into the night in search of survivors trapped in buildings toppled by the strongest earthquake in decades, with at least 21 lives lost and hundreds of people injured.

Tormented families watched with trepidation as soldiers, police and emergency workers sifted through the debris of shredded apartment blocks and hotels in towns near Albania's northwest Adriatic coast, close to the epicentre of the 6.4 magnitude earthquake that hit the country before dawn.

By evening, the death toll was at 21.

Most were pulled from wreckage in the coastal city of Durres and Thumane, a town north of the capital Tirana.

In neighbouring Kurbin, a man in his 50s died after jumping from his building in panic.

Another died in a car accident after the earthquake tore open parts of the road, the ministry said.

Some 42 people have been rescued alive in efforts that continued after the sun went down with headlamps and spotlights.

Earlier in Thumane, locals watching emergency workers comb over a collapsed building shouted the names of their loved ones still inside.

Dulejman Kolaveri, a man in his 50s in Thumane, said he feared his 70-year-old mother and six-year-old niece were trapped inside the five-storey apartment, because they lived on the top floor.

"I don't know if they are dead or alive. I'm afraid of their fate ... only God knows," he said.

There were also brief bursts of joy during the day as rescuers delicately extracted survivors.

One, a thin middle-aged man covered in a film of grey dust, was seen being carried out of the rubble on a stretcher in Thumane.

In Durres, onlookers cheered "Bravo!" as a team rescued a young man from the wreckage of a toppled seaside hotel in a two-hour operation.

Afraid to return home after a series of powerful aftershocks, hundreds of people in Durres took shelter in tents set up in the city's football stadium.

The health ministry said that more than 600 people have received first aid for injuries, mostly minor.

Some 300 soldiers and 1,900 police were sent to Durres and Thumane to assist with the rescue efforts, according to authorities.

Aid also poured in from around Europe, with teams from Italy, Greece and Romania among those deployed to help.

Albania is known for its chaotic urban planning, particularly in popular tourist spots along the coast, where illegal construction is rife.

The quake was the strongest to hit the Durres region since 1926, seismologist Rrapo Ormeni told local television.

Albanian authorities described it as the most powerful quake in the last 20-30 years.

It struck at 3.54am local time (2.54am Irish time), with an epicentre 34km northwest of Tirana, according to the European-Mediterranean Seismological Centre.

In Tirana, panicked residents ran out onto the streets and huddled together after the quake hit.

Several powerful aftershocks followed, including one of 5.3 magnitude.

The tremors were felt across the Balkans, from Sarajevo to Belgrade and the northern Serbian city of Novi Sad almost 700km away, according to reports in local media and on social networks.

The Balkan peninsula lies near the fault line of two large tectonic plates, the African and Eurasian, and earthquakes are frequent.

The movements of the small Adriatic micro-plate also produces earthquakes, according to Kresimir Kuk from the Croatian seismological institute.

The most devastating quake in recent times hit North Macedonia's capital Skopje in July 1963, killing around 1,000 people and destroying some 80% of the city.