Up to 20,000 registered sex offenders will be banned from travelling overseas or holding an Australian passport under new measures signed off by government MPs.
About 400 of the 800 offenders who travelled overseas from Australia in 2016 were in breach of an obligation under state or territory laws to notify police of their intent to travel.
"This is a world first. Australia is leading the way when it comes to protecting vulnerable children overseas from the actions of pedophilia," Foreign Minister Julie Bishop said in Canberra on Tuesday.
"We are ensuring that child sex offenders are not able to take part in the growing child sex tourism trade."
Australian NGO Project Rescue Children works in countries like Cambodia to hunt down child sex tourists.
Founder Adam Whittington says poor countries are a mecca for Australian paedophiles, free to prey on children, un-checked and un-monitored.
"We've known cases where paedophiles go there and offer $10-$20, $5 in some cases, for sexual activities with these kids and these kids have nothing," he told SBS World News.
And he says the trend is spreading, with paedophile travel destinations throughout South-East Asia and Africa.
"Absolutely off this planet out of control," Mr Whittington said. "There's paedophiles walking around on the beach with underage kids and it's just accepted."
Ms Bishop said the proposed laws would be introduced to parliament this week.
Independent senator Derryn Hinch, who was instrumental in convincing the government to take action, welcomed the announcement.
"You go to Bali, you go to Phnom Penh, you go to Siem Reap, and you see these middle-aged Australian men there, Caucasian men, with a young local kid - they're not there to get a suntan," he told reporters.
- with AAP