“With 15.7 percent of Germans in poverty, we have unfortunately reached a high point since reunification,” said Ulrich Schneider, head of the Equal Welfare Association, on Thursday.
The figures are based on statistics from the Federal Statistical Office (Destatis) which records the proportion of the population with an income less than 60 percent of that of the median German household.
In 2005, 14.7 percent of Germans were living below this barrier.
The report by the Equal Welfare Association argued that 12.9 million people in Germany were living below the poverty line in 2015.
“Economic developments have not been reducing poverty for a long time,” said Schneider.
The apparent increase in poverty comes despite unemployment levels falling for years.
In February, unemployment in Germany hung on at an all-time low, official data showed on Wednesday, standing at 5.9 percent - the same level as in January and its lowest level since German reunification in 1990.
People without work and single parents were both particularly vulnerable to poverty, the Equal Welfare Association report stated. A third of all foreigners lived in poverty, while a quarter of all families with three or more children faced this hardship.
Meanwhile the number of pensioners below the Equal Welfare Association's poverty line has risen by 49 percent in a decade, leading Wolfram Friedersdorf - head of the People's Solidarity Association - to speak of an “avalanche” of old-age poverty.
Berlin and the Ruhr region of North Rhine-Westphalia are the regions worst affected by hardship.
But the Equal Welfare Association figures are controversial. Destatis classifies people below the 60 percent mark as “threatened by poverty” as opposed to the Equal Welfare Association's definition, which describes them as poor.
Walter Krämer, a statistics professor at the Technical University in Dortmund, called the statistics “not serious and stupid” in an interview with RedaktionsNetzwerk Deutschland.
“The welfare associations know exactly why they don't want to use serious statistics - because they would show that poverty has been sinking for years,” he said.
Krämer argued that a serious analysis of poverty would involve looking into hardship in real life, such as studies of what people are putting in their shopping trolley.
“But that requires a lot of effort, and for that reason no one does it,” he claimed.