Australian police swooped Thursday on an organised crime gang allegedly plotting to murder four rappers in ONEFOUR, a hip-hop group that featured on Netflix.

The crime ring had been taking on contracts to carry out "serious crimes including murders and kidnappings", New South Wales state police told a news conference in Sydney.

The cell had accepted a contract to murder four "high-profile men" from Mount Druitt, a gritty western Sydney suburb, said Detective Superintendent Peter Faux.

The intended victims were identified in Australian media as members of ONEFOUR, a drill rap group whose members are from Mount Druitt.

Drill is an American style of hip-hop known for lyrics laced with crime and gang warfare references.

Police said they do not publicly identify victims of crime as a matter of policy.

The rap group, which has five core members of Samoan ancestry, starred in a Netflix documentary recounting police efforts to stop them performing in public: "ONEFOUR: Against All Odds".

Police said they raided two places in southwestern Sydney at dawn, arresting two men aged 26 and 20 on charges of conspiring to commit murder, kidnap, and armed robbery.

Another two men are expected to be arrested and charged in relation to the "intended murder", said Faux.

Police have also taken out an arrest warrant on a fifth man believed to be "on the run overseas" over the alleged murder plot, he said.