Describing it as a "contingency planning", the Trade Minister Craig Emerson said that there is nothing unusual about this.
"What has happened there is that embassy is doing its job and that is getting prepared for the possibility of an extradition," he said.
"But having no evidence or certainly I have seen no evidence that the United States is actually preparing to do that," he added.
"All that was happening is that the post in Washington was doing some contingency planning in the event that such an eventuality arose," Emerson was quoted by ABC Television as saying.
Meanwhile, Foreign Minister Bob Carr's office said consular officials have spoken with 41-year-old Assange on eight occasions.
The last conversation was less than two days ago, just before Ecuador granted him asylum.
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A spokesman for Carr said Assange was offered consular assistance, but he thanked them and declined the offer.
Carr reiterated in earlier comments that Australia has no evidence to suggest the US is planning such a move.
He did however confirm that Australia is monitoring a US espionage investigation into American soldier Bradley Manning, who allegedly leaked classified information to the WikiLeaks site.
A spokesman for Carr said that WikiLeaks could potentially be linked to that investigation but it does not mean the US is intent on seizing Assange.
Assange remains at the Ecuadorian embassy as a diplomatic stand-off continues between Ecuador and the UK.
Ecuador has granted him political asylum, but Britain is determined to extradite him to Sweden to face sexual assault allegations.
British police are stationed outside the embassy, ready to arrest Assange if he leaves the building.
Assange has ruffled many feathers by publishing classified diplomatic correspondence of the United States and other countries.