Global aid agency Doctors Without Borders has asked Australia to deploy desperately-needed medical teams to west Africa and has rejected cash for the Ebola response from Down Under.
Canberra offered 2.5 million Australian dollars ($2.2 million, 1.7 million euros), said the charity, known by its Frech initials MSF (Medecins Sans Frontieres).
But MSF said it had reached its logistical limitations and couldn't increase its assistance in Liberia, Sierra Leone and Guinea, the three countries most affected by the epidemic.
"MSF simply does not have the capacity to do this job alone. We are already turning people away from our clinics which have been stretched beyond over capacity for weeks," it said in a statement.
"Australia must stop making excuses to join the fight against Ebola."
The agency said even a small number of Australian healthcare workers would have a "very significant impact".
"Even a dozen trained staff who could oversee local teams to manage an isolation centre, help case finding and outbreak control measures would save thousands of lives today," MSF said.
Paul McPhun, the executive director of MSF Australia, warned the number of infected was doubling every three weeks.
"These are shocking statistics, yet still countries like Australia with the capacity to make a real difference on the ground are looking at each other to take responsibility, and are refusing to send their own personnel to help," he said.
"Facing this reality today, it is unthinkable that Australia is waiting for an invitation from the World Health Organization (WHO) to act."
The outbreak of Ebola, the worst on record, has infected 6,500 people and killed almost half, according to the WHO, although the real death rate, taking into account the delay between reporting infection and death, is likely to be much higher.