The quake-struck Emilia Romagna region in northeast Italy was hit by at least 37 aftershocks overnight, as thousands of anxious people spent a second night in tent camps or their cars.

Tension remains high in the area, with specialists warning that there may be more quakes to come as 14,000 people evicted from their damaged houses tried to come to terms with two earthquakes which devastated buildings and killed 23.

A 3.6-magnitude quake hit near the town of Finale Emilia Thursday morning, terrifying a community hit hard by the first quake on May 20. Some had just found the courage to return home when the second quake hit on Tuesday morning.

Volunteers manning the government's vast blue tent camps said the elderly in particular were suffering, with psychologists on hand to help those finding it difficult to acclimatise to the commotion and heat in the temporary shelters.

The Italian geological council called for Italy's seismic charts to be revised and warned that earthquakes cannot be predicted.

Factories and warehouses were particularly hard hit by the quakes, and many business owners have protested the buildings were not designed for strong quakes because the region has until now been classed as a low-seismic area.

The majority of the victims from both quakes were industry workers and prosecutors in Modena have announced an inquiry into the damage to factories.

"The inquiry will focus on the collapse of recently-built industrial buildings to check whether anti-earthquake norms were respected or if there has been negligence," said prosecutor Vito Zincani.

"These buildings were cheaply built. Today we're paying a much greater price in human lives," he said.

The quakes injured hundreds and brought down historic churches and monuments across the region. The financial fallout for local industry is a severe blow for debt-ridden Italy, which entered into recession late last year.

The latest disasters struck just over three years after a 6.3-magnitude quake devastated the city of L'Aquila in central Italy in March 2009, killing some 300 people and leaving tens of thousands homeless, many of whom are still in temporary accommodation.