The 28-year-old was shot dead when he and his girlfriend Joanne Lees were ambushed near Alice Springs in 2001. His body was never found.
Australian man Bradley Murdoch was found guilty of his murder in 2005. Despite pleas, he has refused to tell authorities where he disposed of Mr Falconio's body.
The Northern Territory police renewed their search appeal on Wednesday, the 20th anniversary of Mr Falconio's disappearance.
"We are thinking of Peter's family and friends on this anniversary and remain hopeful that such a milestone may jolt some information and progress the investigation," said Det Snr Sergeant Karl Day.
Murdoch was jailed for a minimum of 28 years after he was convicted of murdering Mr Falconio and assaulting Ms Lees.
The attack on the British couple in 2001 remains one of Australia's most high-profile criminal cases in recent decades.
Murdoch shot Mr Falconio in the head and assaulted and tied up Ms Lees. She managed to escape, and hid in the bushes for five hours while her attacker stalked her with a dog. She eventually managed to flee to safety after flagging down a passing truck.
Mr Falconio's body is believed to have been hidden by Murdoch somewhere in the vast outback. At his trial, the sentencing judge said he believed Murdoch had taken Mr Falconio's body in his car and dumped it somewhere in the vast outback between Alice Springs and Broome, in Western Australia - a distance of 1,600km (994 miles).
Despite extensive searches and political pressure, police have never found it.
In 2016, the Northern Territory government even brought in a "no body, no parole" law aimed at pressuring Murdoch to reveal Mr Falconio's whereabouts.
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