LYON (AFP) - Twelve Portuguese passengers, including a seven-year-old girl, died when their minibus collided with a heavy lorry on a motorway in central France known locally as "the road of death".

The crash happened late on Thursday night as the minibus was travelling from Switzerland to Portugal, taking the group home for the Easter holidays.

"The 12 passengers of the minibus, who were all Portuguese, are dead," said a statement from the local authority.

Authorities said the bus swerved for an unknown reason and slammed head-first into the lorry on a notorious accident blackspot described by officials as the deadliest in France near the town of Moulins.

The 19-year-old driver of the minibus survived with a fractured wrist.

"He is currently hospitalised, and will be questioned by investigators," said local prosecutor Pierre Gagnoud.

The two Italian drivers of the lorry also suffered injuries but are expected to survive.

All of the drivers took alcohol tests which showed they had not been drinking.

The accident took place on a portion of the Centre-Europe Atlantic Road which crosses from east to west France.

Accidents on the route are common, leading local residents to nickname it "the road of death".

Local newspaper La Montagne reported that the number of road deaths is five times the national average.

The road "is quite monotonous, the speed limit is 90 kilometres per hour. There are those who are impatient and those who fall asleep," said a source close to the investigation, adding that there are only four passing zones in the area.

"They've been talking about adding a second lane for 40 years," he added.

A local official told AFP: "It's the deadliest road in France. When you add it up, we've had 15 deaths in a year." Gerard Deriot, head of the regional council of Allier where the accident took place, said he was "appalled" to see more deaths on the road.

"It is appalling when, for years you have pushed the state to assume its responsibilities" and upgrade the road, said Deriot, from the opposition Republicans party.

Secretary of State for Transport Alain Vidalies said more than 100 million euros (S$153 million) had been set aside in 2016 to upgrade the road.

A local village hall was being used as a temporary morgue and families of the victims were due to arrive later in the day.

The road was closed following the accident, and was expected to re-open later Friday.

The crash comes after after two school bus accidents in February left eight dead in France.