Australian mother and son among the dead in French Alps plane crash.

Two Australians are among 150 people killed in a Germanwings aeroplane crash in the French Alps, Foreign Minister Julie Bishop has said.

Ms Bishop said a woman and her adult son from Victoria were on flight 4U 9525 from Barcelona to Dusseldorf, which went down with 144 passengers and six crew on board.

“I don’t think it gets any easier announcing the death of Australian citizens in a tragedy overseas,” Ms Bishop said.

“Our thoughts and prayers and support are with the family of the victims and we will continue to provide them whatever consular assistance they may require.”

Ms Bishop said Australia will send a consular official to the south-eastern French town of Gap where they will set up a mobile office and liaise with French authorities on the recovery effort.

Tony Abbott also offered his condolences to the families who have lost relatives.

“Our thoughts and prayers are with the friends and families of all those killed but particularly with the loved ones of the two Australians who have lost their lives,” Mr Abbott said.

“Our consular officials are doing what they can for the families.”

Grieving relatives of passengers gathered at Barcelona and Dusseldorf airports as officials announced none of the 150 people on board survived.

Police at the remote crash site in south-eastern France said everyone on board was killed when the Airbus 320 operated by Lufthansa's budget carrier Germanwings went down.

The airline's managing director Thomas Winkelmann said routine maintenance of the aircraft had been carried out the day before, and said the company would work closely with investigators.

With the cause of the accident a mystery, authorities have recovered a black box from the Airbus A320 at the crash site, where rescue efforts were hampered by the mountainous terrain.

French officials halted the recovery operation at nightfall, when the weather deteriorated.

Local MP Christophe Castaner, who flew over the site, said on Twitter: "Horrendous images in this mountain scenery. Nothing is left but debris and bodies.

"A horror - the plane is totally destroyed."

A senior airline official said they were working on the assumption the crash was an accident.

"For the time being, we say it's an accident, anything else would be speculation," Lufthansa vice president for sales and services in Europe, Heike Birlenbach, said.

It is believed 67 German and 45 Spanish nationals were on board the flight, including two babies.

Also believed to be among the victims were 16 children and two teachers from the Joseph-Koenig-Gymnasium high school in the town of Haltern am See in north-west Germany, a spokeswoman said.

Local mayor of Llinars de Valles, a town north of Barcelona, Marti Pujol, said pupils were in shock at a local high school where 16 of the passengers on the plane had just attended an exchange program.

"We have the Red Cross and psychologists there. The teachers were in the school and are looking after the children. This affects the whole school, which has more than 400 pupils," Mr Pujol said.

He said the children were aged about 15. It was a reciprocal visit after 12 Spanish students had spent a week at their school in December.

"The students were informed that there was a sufficient probability that the plane would not be landing in Dusseldorf," Haltern am See mayor Bodo Klimpel said.

"Classes were then called off."

The students were sent home but many returned in the afternoon with candles in their hands and tears in their eyes to mourn with each other at the school.

Mr Klimpel said some parents drove to the airport and some to the school.

"It's the darkest day in this town's history," Mr Klimpel said.

"We're in a state of shock. It's the worst thing ever imaginable."

Spanish prime minister Mariano Rajoy said he had set up a crisis cell to deal with the disaster, calling it "tragic and sad news", and that he would visit the scene on Wednesday.

Psychologists and social workers were attending to the families at Barcelona airport, Red Cross spokeswoman Irene Peiro said.

"When they are told the news they have grief and trauma and we try to minimise as much as possible these traumatic, anxious and uncertain moments," she said.

A group of police stood guard around the Lufthansa Germanwings stand but Lufthansa check-in desks were operating normally.

French prime minister Manuel Valls said he had also called an inter-ministerial crisis cell.

"We don't know the reasons for the crash, we clearly fear that the 150 passengers and personnel have been killed considering the circumstances of the crash," Mr Valls said.

"All is being done to understand what happened and to help the families of the victims," he said.

Opera singers among passengers, narrow miss for footballers

Two star opera singers, one of them accompanied by her baby, were among the 150 passengers, theatre officials said.

Bass-baritone Oleg Bryjak, 54, and contralto Maria Radner, 33, were flying to their home city of Dusseldorf after starring in Richard Wagner's opera "Siegfried" at Barcelona's opera house, the Gran Teatre del Liceu.

The theatre said Radner was travelling with her husband and baby -- one of two infants to perish on the flight, according to officials.

"The Liceu theatre wishes to express its condolences for the passing of the singers Oleg Bryjak and Maria Radner, as well as her husband and baby in the accident suffered by the plane bound from Barcelona to Dusseldorf," it said.

Meanwhile, a Swedish third-division football team booked on the doomed flight escaped death by changing flights at the last minute, the team said.

The Dalkurd FF team from Borlaenge, in central Sweden, was booked to fly home to Sweden on the budget carrier after a trip to Catalonia.

Sporting director Adil Kizil told daily Aftonbladet the team had a very close call.

"We were supposed to be on that plane," Mr Kizil said.

"There were four planes that left around the same time and that flew north over the Alps. Four planes and we had players on three of them. You can say we were very, very lucky," he said.

No Mayday call sent

French civil aviation authorities said they lost contact with the plane and declared it was in distress at 10:30am (8:30pm AEDT).

"The crew did not send a Mayday. It was air traffic control that decided to declare the plane was in distress because there was no contact with the crew," an official said.

US president Barack Obama offered the United States' condolences to both countries following the crash.

"It's heartbreaking because it apparently includes the loss of so many children, some of them infants," Mr Obama said, adding that he had called Germany's chancellor Angela Merkel and would call Spain's prime minister Mariano Rajoy.

"Our teams are in close contact, and we're working to confirm how many Americans may have been on board. Germany and Spain are among our strongest allies in the world."

This article originally appeared on the ABC and was republished here with full permission.