While the Federal Government says it will not send troops or medical personnel to fight Ebola, at least 12 Australians are already on the front line of the outbreak in Africa.

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Meanwhile, a range of new precautions to prevent the deadly virus entering Australia have been put in place.

Australia has been screening passengers returning from West Africa since early August, Australia's chief medical officer Professor Chris Baggoley said.

"People returning from Nigeria, Liberia, Sierra Leone and Guinea have been taken aside from passport control," he said.

"Biosecurity staff ask whether they have been in contact with Ebola patients, whether they attended funerals, or whether they have had a fever in the last 24 hours."

In the two months to mid-October, authorities screened more than 700 passengers at 10 Australian airports.

A new system has been set up to alert authorities when Australian healthcare workers leave for Ebola-affected areas, and when they return to Australia.

Médecins Sans Frontières Australia says it has 12 Australians and two New Zealanders in the field in Liberia and Sierra Leone.

They include logisticians, medical doctors, nurses, epidemiologists and field administration officers.

The Red Cross has one worker in Sierra Leone, one coming back, and three other workers leaving this week.

So far, 11 Australians have been tested for the Ebola virus, with none returning a positive test.

In the most recent case, Sue Ellen Kovack, 56, was hospitalised in Queensland after returning from treating Ebola patients in Sierra Leone as a volunteer with the Red Cross.

After two negative tests, the nurse was discharged from Cairns Hospital.

Australian Red Cross spokesman Peter Walton said he was pleased safety procedures for returning aid workers were proving effective.

"It’s a credit to the bravery and courage of people like this that they're able to go and assist on the front line, but also respect the protocols when they return so there's no chance of putting anyone at risk," Mr Walton said.

Health workers at increased risk

ANU infectious diseases expert Professor Peter Collignon said health workers appeared to be at increased risk of contracting Ebola, despite taking precautions.

Two health workers in the US and one in Spain have tested positive for Ebola after caring for infected and seriously ill patients.

"As we have seen in Dallas and Spain, there's no doubt health workers can become infected," Professor Collignon said.

Sorry, this video has expired Screenings, alert systems to protect Australia

"They took all the proper precautions like taking personal protection equipment on and off properly."

Tom Frieden from the US Centres for Disease Control admitted it needed to rethink the way medical staff addressed Ebola infection control.

"We have to work together to do whatever's possible to reduce the risk that any other healthcare worker becomes infected," Mr Frieden said.

Professor Collignon said Australian health authorities may also need to look at why healthcare workers were getting Ebola despite using personal protection equipment.

"It may be that when health workers are donning and doffing the gear we need some new precautions... someone else may have to oversee that process so that it is done without any cross contamination," he said.

Professor Collignon believed Australia was prepared for Ebola.

"To some degree, the reason it has spread in countries such as Sierra Leone is because standard procedures such as the use of gloves are not followed," he said.

"In Australia we are prepared to stop any spread.

"We know we can diagnose it quickly, as the negative tests have shown, and we have proper containment facilities."

Can Australia do more?

Health groups have put pressure on the Federal Government to send Australian medical experts to Ebola hotspots.

The Australian Medical Association and the Public Health Association of Australia have asked the Government to send staff and support teams to West Africa to help contain the outbreak.

Prime Minister Tony Abbott said he was not confident all the risks were being properly managed, and ruled out sending Australians.

"We are not going to send Australian doctors and nurses into harm's way," Mr Abbott said.

Australia allocated $18 million in funding to combat the disease.

The United States has sent 3,000 troops to West Africa to help combat the spread of Ebola.

"There's a world of difference between praising the selflessness of volunteers and ordering Australian personnel to go into a situation without the kind of risk-minimisation strategies that any responsible Australian government would put in place," Mr Abbott said.

Health experts said there is a chance the Ebola virus could arrive in Australia, but most believe the risk of it spreading remains extremely low.

Along with increased border control, GPs are being urged to be vigilant in case someone with Ebola presents with symptoms at a doctor's surgery.

"GPs should be alert to the possibility of Ebola in unwell travellers returning from affected areas of West Africa," Professor Baggoley said.

"They need to immediately apply appropriate infection control measures and contact public health agencies urgently to discuss patient transfer to hospital and the management of contacts."

A version of this article also appears on The Brief.