The handling of the girl's case has caused public outrage in Romania. (AFP)

The family of a 15-year-old Romanian girl kidnapped earlier this month and now presumed dead has released recordings of her desperate calls for help to authorities whose handling of the case has caused public outrage and dismissals of officials.

A mechanic from Caracal in south Romania has confessed to killing Alexandra Macesanu, who went missing on July 24, and another 18-year-old girl last seen in April.

With authorities taking 19 hours to locate Macesanu after she made three calls to the emergency number 112, the case has sparked street protests, the interior minister's resignation, and the firing of some local officials.

"Please stay with me on the line, I'm really scared," Macesanu told a policeman while crying during her third and last call, according to a transcript released on Facebook by her uncle Alexandru Cumpanasu late on Tuesday.

"I can't stay on the line with you, miss, I have other calls," replied the officer Vasilica Viorel Florescu, according to the transcript and audios. "Stay there, a police car will come without fail, in 2-3 minutes ... what the hell, calm down, the car is en route."

Reuters has been unable to independently verify the audios, and neither the Special Telecommunications Unit (STS) in charge of directing 112 calls, police nor the Interior Ministry responded to requests to confirm them or comment on their contents.

The uncle, who has acted as a spokesman for the family, said when he released the transcripts that the parents have asked the media not to use their daughter's voice.

Some Romanian media, however, have broadcast what they said were leaked fragments of the call, so later on Tuesday Cumpanasu released the entire audio recordings, which he had requested from the STS.

Florescu, a policeman from the nearby town of Slatina, told local media that he talked to Macesanu twice out of the three calls she made, including the last one, and gave her details to Caracal police.

"I repeatedly told her to stay calm and that a police car was coming," he was quoted as saying by the private television station Romania TV. He added he disconnected the call so that local police could get in touch with her.

Reuters could not immediately reach Florescu for comment.

Human remains have been found at the house of 65-year-old mechanic Gheorghe Dinca, where Macesanu was kept. A preliminary forensic report is expected on Friday.