Local media quoted court documents saying the substance was asbestos, a cancer-causing material once widely used in construction, but a police spokeswoman declined to confirm or deny the reports.
A court artist sketch by Paul Tyquin of Savas Avan who faced Melbourne Magistrates Court on Thursday charged over suspicious packages sent to embassies and consulates across Melbourne, Canberra and Sydney.
Police arrested the 48-year-old man last night at his home in Shepparton, a 100km north east of Melbourne.
Savas Avan, 49, faced Melbourne Magistrates Court on Thursday charged with sending unsafe items by post.
On Wednesday suspicious packages were received at embassies in Canberra as well as the US, Pakistani, Swiss, Indian, South Korean, New Zealand, Greek, French, Italian, Spanish and Turkish consulates in Melbourne.
Officers have so far recovered 29 of the packages, with forensic testing now underway to determine the exact substance in them.
There was no ongoing threat to the public, authorities said.
"Police have identified all intended recipients and have put processes in place to recover the outstanding packages", the AFP said in a statement.
Chelsea Closing In On Gonzalo Higuain
He was hampered by a back injury earlier in the season but broke a two-month goal drought just before the winter break. Higuain enjoyed his best run of form under Sarri, scoring 37 goals with the Italian boss prior to moving to Juventus .
Emergency crews were called to several consulates on Wednesday after being alerted by staff.
The powder, contained in clear plastic bags within an envelope, was subsequently deemed not unsafe.
One New Zealand official told the ABC their consulate received a similar package. They gave no additional details of how the asbestos was packaged or what the motive might have been.
"Today [Wednesday] we received communication from the diplomatic body here in Victoria that there are suspicious packets circulating and that we should contact the police if we've received something and we have contacted the police", Botsiou said, translated from Greek.
Around 10 diplomatic missions, mostly in Melbourne, on Wednesday reported the delivery of suspicious packages, some of them labelled "asbestos".
"They were very quick on to it, they provided advice to the relevant consular residences and in practical terms we learnt very quickly, that evening, that the substance was inert", he said.
The packages were delivered Wednesday.