Those detained include a laboratory technician, an anaesthetist and a service worker, who were reportedly caught receiving amounts ranging from 30,000 to 50,000 meticais.
According to a source linked to the case, the three employees were allegedly part of an illegal payment scheme involving patients at the health facility.
Following their arrest, the three were taken to the Second Police Station of the Republic of Mozambique Police in Xai-Xai, where they remain in custody.
Investigations are continuing and also involve other hospital staff. An orthopaedic doctor and a radiology technician are reportedly under investigation on suspicion of involvement in the same scheme.
The case comes about a month after allegations of illegal payments were reported at the maternity ward of Xai-Xai Provincial Hospital, alongside complaints over difficulties in accessing medicines and frequent power cuts.
Authorities are expected to continue investigating the extent of the alleged scheme, identify any other individuals involved and establish the responsibilities of those detained.
The Republic of Mozambique Police is expected to provide further information on the case and clarify the next steps in the investigation.