Bacterial powder sent to Indonesia's embassy in Canberra, sparking a security scare, was probably harmless, Australian police have said.
Embassy workers were put in quarantine
They did say, however, that tests on the mystery package would continue.
The Australian authorities have linked the case with public anger over Indonesia's jailing of a 27-year-old for smuggling drugs into Bali.
Schapelle Corby, who was given a 20-year sentence, has maintained her innocence throughout her trial.
Australian Federal Police commander John Davies said preliminary tests on the powder found it contained a bacteria, but it was unlikely to be anthrax or other agents harmful to humans.
"It is unlikely to contain material of pathological significance," he told reporters.
The powder, found in a parcel addressed to Indonesia's Ambassador to Australia Imron Cotan, forced the embassy to shut on Wednesday and quarantine its staff for 12 hours.
None has shown symptoms of illness.
Australian Prime Minister John Howard apologised to Jakarta, saying many Indonesians would see the incident as damaging to bilateral relations.
He said the attack was "reckless" and would not help Corby's case, who lodged an appeal on Wednesday. Opinion polls suggest 90% of Australians agree with her version of events.
The beautician from Queensland has repeatedly said her luggage was tampered with, after she was arrested last October with 4.1kg of marijuana in her bags at Bali airport.
Many Australians now say they would boycott Bali, a destination desperately in need of tourists after the disastrous impact of the October 2002 bombing.
The Australian government has urged people to accept the verdict, but said it will supply lawyers to help Corby's appeal.