Jacqueline Zwambila condemned President Robert Mugabe's government, and said she has moved out of her official residence but has no intention of using her business class ticket to return home.
"I don't feel safe about returning to Zimbabwe at all," said Zwambila, who is aligned with Zimbabwe's opposition Movement for Democratic Change (MDC).
"Once the elections of 31 July were stolen by the current government -- which is illegitimate -- I knew that this was the end of the line," Zwambila, whose tenure as ambassador ends on Tuesday, said in a video posted on the Canberra Times website.
"End of the line for the people of Zimbabwe... and for people like me, who were appointed by the ex-prime minister Morgan Tsvangirai."
Zwambila said she was seeking a protection visa from Australia so she can stay on in the country along with her family once her diplomatic status expires. But it was not immediately clear whether Canberra would approve her request.
Mugabe, Africa's oldest leader who has been in power for 33 years, began a new five-year term after winning a landslide victory in disputed elections end of July.
His rival, opposition leader Morgan Tsvangirai, described the vote as "fraudulent", citing an unusual number of voters had been turned away in urban constituencies that are considered opposition strongholds.
Australia, which had offered reduced sanctions as an incentive for free and fair elections, joined the United States and Britain in questioning the credibility of the polls and called for a re-run.
But the 89-year-old veteran leader dismissed the view, brusquely telling his opponents to accept defeat.
Zwambila said that when she learned about Mugabe's victory, she saw "doom, a black cloud".
"I knew then it was the end of my term," the report quoted her as saying.
She voiced fears of indefinite detention if she returned home, saying she had been threatened with arrest in Zimbabwe after a court found that she owed several hundred dollars to a tradesman. She denied the charge.
"So many things have been done to me since I've been here in Australia, the smear campaigns and threats... There is no way I feel safe being in Zimbabwe or going back to Zimbabwe," she said.
Mugabe, who has led Zimbabwe since independence in 1980, is serving under a new constitution and has not ruled out running again when he will be 94.
Tsvangirai had shared power with Mugabe until the July elections, with his MDC party controlling the finance ministry after they forged a unity government in 2009 following violent disputed polls.
But the shaky power-sharing deal ended when the veteran president won the July 31 polls with 61 percent against his rival's 34 percent.
