The Yi Peng 3 and Eagle S are both suspected of being part of a so-called shadow fleet of oil tankers that Russia is using to avoid Western sanctions imposed since the full-scale invasion of Ukraine.

A Chinese ship, the Yi Peng 3, was suspected of dragging its anchor over the cables in a separate act of Russian sabotage.

Matthew Norman, Scott Rush, Martin Stephens, Si Yi Chen, and Michael Czugaj arrived back in the country on Sunday following years of lobbying by Australia on their behalf.

Prime Minister Anthony Albanese wrote on social media: "I am pleased to confirm that Australian citizens, Si Yi Chen, Michael Czugaj, Matthew Norman, Scott Rush and Martin Stephens have returned to Australia this afternoon."

"Chinese authorities must reverse this unjust verdict, and protect the right of journalists to work freely and safely in China," Beh Lih Yi, Asia program manager at the Committe to Protect Journalists told Reuters.