Ebola tests on two young sisters at Melbourne's Royal Children's Hospital have come back negative for the virus.

The pair were placed into isolation after being transported from Melbourne Airport with elevated temperatures at 1:30am (AEDT) this morning.

The girls are from a family of five who had arrived back in Australia on Etihad Airways flight EY460 after spending time in the West African country of Guinea.

They were tested for a range of diseases, including the Ebola virus, at the Royal Children's Hospital in Melbourne.

The girls have suffered a respiratory infection but are expected to make a full recovery.

Earlier, Victoria's Chief Health Officer said it was unlikely the pair had contracted the deadly disease.

"There is no evidence of these patients being at risk of contracting Ebola Virus Disease - and the initial clinical assessment has suggested it is exceedingly unlikely," Dr Rosemary Lester said in a statement.

The Royal Children's Hospital confirmed the children had been isolated following admission this morning "with an infectious disease".

The Royal Children's Hospital in Melbourne. (9NEWS)

"The children, aged under 10, are being tested for a range of infectious diseases, including the Ebola virus," a statement from the hospital read.

"Specialist medical staff are caring for the patients, using the procedures and equipment in which they have been trained. The safety of staff and the community is paramount.

"Results of the diagnostic testing will be known within a few hours. The hospital is unable to provide further information about the patients or their conditions until the test results are known.

Ambulance Victoria State Health Commander said paramedics had followed standard procedures for infectious diseases and used personal protection equipment.

Several Australians have been tested for Ebola since the deadly outbreak in West Africa last year but there have been no positive results recorded here.

The disease is only spread through contact with the bodily fluids of an infected person or animal.

A person is only infectious once symptoms - such as fever, muscle pain and headache - begin to show.