"We are striving, just like all the other authorities in the city, the police, the fire services, to create clarity," a Moabit Hilft spokeswoman told journalists at a press conference on Wednesday afternoon.
She added that the man who reported the death had "barricaded himself" in his apartment and was refusing to speak with anyone.
"It would be a catastrophe for us [if the helper had made up the story]," the spokeswoman said. "We simply wouldn't be able to trust many of our helpers any more."
"We have to believe that our people have enough intelligence not to make up a story like this."
According to the spokesman, the volunteer was a "very active helper" who had contributed a lot to their project to help refugees waiting to be processed at the Berlin Health and Social Affairs Office (LaGeSo).
But a spokeswoman for the LaGeSo told Spiegel Online late on Wednesday that "we have called all the hospitals [and] there is no information there about this case."
News of death spread online
News of the alleged death had spread early on Wednesday morning through Facebook posts shared by volunteers.
"Now it's happened. Just now a 24-year-old Syrian who waited in the slush in sub-zero temperatures – DEAD after fever, shivering, and cardiac arrest in the ambulance," Reyna Bruns posted on Facebook early on Wednesday morning.
"The man who has now died was 24. One of the 'young, healthy men' who can take on anything, that no-one needs to take care of, and who are looked on with suspicion from the start – what can they want here?" she added.
Bruns included a transcript of a chat with a volunteer by the man's side, describing the man's worsening condition and eventual death of cardiac arrest in an ambulance on the way to the hospital.
Tributes quickly collected outside the Lageso, with refugee helpers leaving candles in front of one of the building's doors.
Candles left outside the Berlin Health and Social Affairs Office on Wednesday after the reported death of a refugee. Photo: DPA
'Direct consequence of situation at Lageso'
Bruns also said that there had been at least four miscarriages among women waiting at the Lageso - "is that not also a death?", she asks – as well as several resuscitations, heart attacks, diabetic shocks and collapses.
"This sacrifice of a human life ought to have been prevented. We all saw it coming. And not just for the past two days. For the past half a year."
Fellow volunteer Diana Henniges had earlier told Spiegel Online that the reported death was a "direct consequence of the waiting situation at the Lageso."
"He was drained from waiting in the cold, he had a flu-type infection. By the end he had to show up at the Lageso even when he had a fever," Henniges said – adding that the Syrian refugee had also been unable to get money for food.
Organization under pressure
The Lageso has been under pressure for months over poor management, with the former boss forced to step down in December.
Henniges told The Local at the time that "of course we don't expect anything to change" just because the face at the top has been switched and went on to accuse the Berlin Senate of letting refugees down.
Over 40 lawyers filed a criminal complaint against the city's health senator Mario Czaja in December, alleging institutional neglect was "causing bodily harm".
"In no other state are politicians and administrators failing as systematically as here," charged lawyer Christina Clemm at the time, claiming the result was injuries, illnesses, hunger and homelessness.