You need an embassy visa for Turkmenistan if you have an Australian passport
Visa options for Turkmenistan
Visitor visa
Travellers need a visa to visit Turkmenistan for Business or Tourism. A paper or embassy visa is the only visa available for travellers visiting Turkmenistan. The visa is typically a stamp or sticker added to the passport. Travellers must obtain this visa from a local embassy, consulate or visa center before travelling.