Sirul is reported to be in Australia since November without any money to return to Malaysia to face the sentence.
The Sydney Morning Herald said Australia's extradition laws do not allow it to send home a person who has been sentenced to death, unless it is assured that the person would not be given the death sentence.
A spokesperson from the Australian Attorney-General's Office said the reason for refusing to extradite Sirul was because the country was against capital punishment.
On Tuesday, the Federal Court convicted Sirul, 43, and C/Insp Azilah Hadri, 38, of murdering Altantuya.
The Apex court ruled that the prosecution had proven its case against the two accused beyond reasonable doubt.
It was reported that Sirul did not have money to return to the country.