"Iran cannot be allowed to develop a nuclear weapon. We support action to prevent that from occurring, and this is what this is," Foreign Minister Penny Wong told reporters.

"What happens now matters. We do not want to see escalation. We do call for diplomacy, de-escalation and dialogue because the world does not want to see full-scale war in the Middle East."

The US attacks had targeted sites specific to Iran's nuclear program, she said, citing the UN nuclear watchdog's findings that Tehran's uranium enrichment breached its international obligations.

Australia's conservative opposition has also supported the US military action, though the smaller Greens Party has condemned it as a "blatant breach of international law".

Australia's security strategy is deeply entwined with its relationship with long-time ally the United States.

In 2021, it joined with the United States and Britain in a multi-decade pact to equip the Australian navy with stealthy nuclear-powered submarines, seeking to balance China's growing military strength.