Assistant Defence Minister Matt Thistlethwaite says Ukraine President Volodymyr Zelenskyy was "very appreciative" of Australia's $250m military assistance package for Ukraine.
The military support package, which includes air defence missiles and anti-tank weapons, was announced overnight by Defence Minister Richard Marles who was in Washington DC at the NATO summit.
Mr Thistlethwaite, who also attended the summit, described the commitment from other NATO defence ministers to assisting in "the defence of Ukraine and repelling Russia's illegal invasion" as "rock solid."
"I had a number of meetings with congressional representatives from both sides on Capitol Hill about AUKUS and about Ukraine and I can tell you their commitment to the defence of Ukraine is steadfast as well," Mr Thistlethwaite said.
"I think there's a collective commitment there, and indeed a commitment within the United States Congress to continue that important support."
Mr Thistlethwaite dismissed fears about what would happen to support for Ukraine and AUKUS if Donald Trump was to become the next president of the US, saying Australia's alliance had survived regardless of which administration had been in office in Washington and which government had been in office in Canberra.
"Obviously what happens in November, there is a matter for the American people," Mr Thistlethwaite said.
"The meetings I had this week only reinforced to me the steadfast commitment that the American people have, and indeed, the American Congress has, to continuing that support for AUKUS and indeed more broad scale support for their partnerships through NATO."
Lily McCaffrey