A group of failed Afghan asylum seekers was sent on a flight out of Germany on Tuesday, the first time in more than three months after the practice was temporarily suspended due to a truck bombing outside the German embassy in Kabul that killed 150 people.

At least 12 failed Afghan asylum seekers left from the western city of Dusseldorf for Kabul late Tuesday, according to a refugee advice centre in the western state of North Rhine Westphalia.

Some 180 human rights activists gathered at Dusseldorf airport on Tuesday evening to protest the group deportation, according to police estimates.

The demonstrators held up signs that read "Stop Deportations" and "No Deportations to Death."

There were no incidents during the protest, a police spokesman said.

After the terrorist attack in Kabul on May 31, the German government suspended the regular group deportations of Afghans, which began in December as Berlin sought to show it was tackling the high number of migrants by removing those who do not qualify as refugees.

Refugee rights group Pro Asyl denounced Tuesday's planned deportation as a campaign tactic by the government just 12 days ahead of a federal election in which Chancellor Angela Merkel is seeking a fourth term.

"This is an effort to send a signal of strength shortly before the election in order to fish for votes in anti-immigrant circles," said Pro Asyl's chief executive Guenter Burkhardt.

North Rhine Westphalia's integration minister, Anne Spiegel, of the opposition Green party, criticized the fact that the situation for the deportees was not safe in large parts of their home country.

"What plagues me with great concern is the high number of victims in the civilian population," Spiegel said on Tuesday in the city of Mainz.

The most recent report from Germany's foreign and interior ministries on the situation in Afghanistan had too little about the security situation for the civilian population, Spiegel complained.