An Italian court has ruled some of the victims of the 2009 L'Aquila earthquake were partly to blame for their own deaths and compensation for their relatives should be reduced, media reports said Wednesday.

The 6.3-magnitude earthquake struck on April 6 at 3.32am, after months of tremors across the rugged Abruzzo region in central Italy. Houses collapsed throughout L'Aquila's historic centre, killing 309 people.

The judge in a civil suit for millions of euros in damages, presented by relatives of 24 people who died in one of the buildings, said the victims had gone back to bed despite two tremors earlier in the night.

That "rash behaviour" made them "30% responsible" for their deaths, she said, according to the Messaggero daily.

Maria Grazia Piccinini, a lawyer and the mother of Ilaria Rambaldi, a 25-year-old student who died, said the ruling on Tuesday was "absurd" considering experts had played down fears of a killer quake.

"My daughter was reassured, just like everyone else," Piccinini told the Corriere della Sera, adding that they would be appealing the ruling.

Seven members of Italy's Major Risks Prevention Commission were initially convicted over advice given to residents before the disaster, though all but one of those would later be overturned.

The quake, which reduced L'Aquila's elegant medieval, Renaissance and Baroque squares and buildings to rubble, left 1,600 people injured and at least 80,000 people homeless.