Malcolm Turnbull has dismissed concerns Australia might be dragged into war by Donald Trump after the Greens described the US president as "dangerously unhinged".

It was not the president who was a threat to Australia's security, the prime minister told parliament on Thursday.

It was the policies of the Greens, including the minor party's call for a parliamentary debate on any overseas troop commitment.

"I'm standing up for Australia's security. You, the Greens party, would undermine it at every turn," Mr Turnbull told MP Adam Bandt, adding the US alliance was the foundation of national security.

"Whenever we commit our troops, we do so in the national interest of Australia."

Americans understood they had "no truer ally, no more resolute friend, than Australia".

"We have stood together again and again, in freedom's name, in our national interest," Mr Turnbull said.