Central Chile faces increased risk of a very large earthquake close to the site of last February's 8.8-magnitude temblor that killed 520 people and cost 30 billion dollars, scientists said on Sunday.

In a study published online by the journal Nature Geoscience, seismologists looked at a notorious fault which has produced six quakes since 1835, including a world-record 9.5 event in 1960.

Pressure along the fault was not eased by last year's quake in the Maule region and in fact has probably increased in a patch located inland to the east and north of the city of Concepcion, they said.

"We can conclude that increased stress on the unbroken patch may in turn have increased the probability of another major to great earthquake there in the near future," the paper warned.

Lead author Stefano Lorito, of Italy's National Institute of Geophysics and Vulcanology, said in response to emailed questions from AFP that the quake, if it happened, could have a magnitude of "seven to eight."

"It is a zone quite close to the epicentre of the Maule 2010 event," he said.

The study did not attempt to forecast when the quake would occur, a question that is always elusive in seismology, he said.

The February 27 2010 quake, which occurred just off the coast 115 kilometres (70 miles) north of Concepcion, unleashed a tsunami that swept away entire villages.