Medecins Sans Frontieres was told on Friday its free psychological and psychiatric services, provided to both Nauruans and refugees since November 2017, were "no longer required".

MSF (or Doctors Without Borders) was given 24 hours to cease operations which is comprised of a clinic at the Republic of Nauru Hospital and home visits.

The organisation indicated a desire to find a way to continue its work.

"At this stage MSF wishes to reiterate our strong commitment to providing quality mental health care to all those in need on the island," a spokesperson said.

"We are extremely concerned that the health of our patients may be affected by this decision and urge the authorities to grant us permission to continue our lifesaving work."

The abrupt dismissal follows a report by two prominent Australian refugee organisations saying most refugee children on Nauru are experiencing life-threatening mental health problems, including not eating or drinking and suicidal symptoms.

Advocacy group Refugee Action Coalition said MSF's absence would "add enormously to the distress among asylum seekers and refugees" because the Australian government's contracted mental health care provider, International Health and Medical Services, was "stretched to breaking point".

The Department of Home Affairs said on Saturday MSF's dismissal was a matter for the Nauruan government and that it would continue to provide "appropriate healthcare and mental health support to refugees and asylum seekers through contracted service providers".

MSF uses more than 30,000 doctors, nurses and other mostly volunteer personnel to provide medical aid in over 70 countries.

Australian Associated Press