Families of victims of an air strike in Afghanistan that killed more than 90 people in 2009 have filed a multimillion-dollar class-action lawsuit against Germany, a lawyer said Friday.

Karim Popal, an attorney representing the plaintiffs, said 10 class action lawsuits were claiming 3.3 million euros ($4.4 million) in damages from the German government.

"Many orphans and widows lost their providers due to this barbaric war crime, and many mothers their young children," Popal said in a statement.

"Nearly all the survivors are traumatised and are not receiving psychological treatment."

In response to a sharp rise in attacks on foreign forces, a German commander on September 4, 2009 called in a raid near the northern Afghan city of Kunduz. The strike claimed 91 victims according to the German government and up to 142 people including dozens of civilians according to Afghan officials.

A spokesman for the regional court in the western city of Bonn told AFP that it had received 10 complaints claiming damages from the German government but declined to provide further details.

Popal had already filed class-action lawsuits in 2011 demanding $33,000 per victim and said the plaintiffs were still awaiting a ruling from the same court in Bonn.

The air strike prompted public outrage just weeks before a German general election, forcing the defence minister at the time to resign and putting Chancellor Angela Merkel under pressure to clearly define her Afghan policy.

The defence ministry approved compensation in 2010 of $5,000 per family. A ministry spokesman said Friday that 90 families had received payouts to date.

Popal told AFP his firm was representing a total of 426 people from 79 families in litigation against the German government.

Germany currently has around 4,800 troops in Afghanistan, the third largest contingent under NATO's International Security Assistance Force.