Correction: An earlier version of this article did not make sufficiently clear that the allegations mentioned below concerned specifically the US Red Cross society and not the international organisation as a whole.

After raising about $500m in donations meant to help rebuild Haiti following the 2011 catastrophic earthquake, the US Red Cross managed to only build a meagre six homes in the country, according to a joint investigation by the news outlets Pro Republica and NPR.

The prominent US aid organisation said it had provided homes to more than 130,000 people, "but the actual number of permanent homes the group has built in all of Haiti is six", the report released on Wednesday said.

The statement unveiled how rampant mismanagement, inflated salaries of employees, and a lack of transparency fuelled the squandering of millions of dollars by the US Red Cross society.

It also suggested that the funds raised for Haiti could have been misallocated by the aid group to wipe off at least $100m worth of debt.

"The Red Cross has celebrated their work, saying it has helped more than 4.5 million Haitians to get back on their feet," the report said.

But Jean-Max Bellerive, Haiti’s prime minister at the time of the earthquake, doubts the figure, pointing out the country’s entire population is only about 10 million.

"No, no," Bellerive said of the US Red Cross' claim, "it's not possible".

Pro Republica and NPR said that after the US Red Cross declined to show the results of its housing projects in Haiti, the news agencies sent a team to the Caribbean country to investigate one of the group's plans earlier this year.

Jean Jean Flaubert, the head of a community group that the US Red Cross society set up as a local sounding board, "pointed to the lack of progress in the neighbourhood and the healthy salaries paid to expatriate aid workers".

"What the Red Cross told us is that they are coming here to change Campeche. Totally change it," said Flaubert. "Now I do not understand the change that they are talking about. I think the Red Cross is working for themselves."