With US President Donald Trump talking up his plans for more nuclear weapons, Russia's Vladimir Putin has also announced an array of missiles he says could hit almost any point in the world.
"These are dangerous times," Mr Turnbull told reporters on Friday in Sydney where he was meeting with New Zealand Prime Minister Jacinda Ardern.
"Our focus right now ... is in doing everything we can to prevent and arrest nuclear proliferation.
"The most stark example is in North Korea, where we are working with our allies and indeed with international partners, including China, in seeking to enforce strict economic sanctions in North Korea to bring that regime to its senses."
But he said Australia would be sticking to its opposition to signing up to a United Nations ban on nuclear weapons.
"The weakness of it, from our perspective, is that the nuclear powers are not a party to it," Mr Turnbull said.
"We work internationally to prevent proliferation. We clearly, all of us, would like to aspire to a world which is free of nuclear weapons but we have to focus on the here and now."
Ms Ardern said NZ's firm stance against nuclear proliferation had "become part of our identity as a nation".
"We are seeking to expedite the ratification of that (treaty)," she said.
