Azealia Banks and Sia have been involved in a war of words over Banks' decision to slaughter animals as part of witchcraft. Getty/Instagram

Azealia Banks has launched a lengthy racist rant at pop star Sia, after the Australian pop star criticised the rapper for sacrificing animals as part of witchcraft practices.

The war or words began on Twitter when Sia responded to a video on Banks' Instagram feed, in which the rapper claimed she was cleaning after using it to slaughter chickens for three years for the last three years.

The 41-year-old described Banks' claims as the "wackest shit I've ever heard", encouraging the 212 hitmaker to "get ahead by being awesome, kind and working hard".

Banks, known for her twitter spats and online insults, did not take kindly to the advice – launching into a tirade, saying: "HAVE SOME F*****G RESPECT FOR MY F*****G TRADITIONAL AFRICAN RELIGION YOU POMPOUS WHITE B*TCH".

The 25-year-old, whose career has stalled since her breakthrough in 2011, went on to mock Sia for obscuring her face during live performances.

"And your ugly pasty dry white lady winter skin face is the ugliest face I've ever seen that must be why you hide it all the time," she added.

It is not the first time Banks has made controversial remarks on social media. Back in May, she was suspended from Twitter after a foul-mouthed tirade at Zayn Malik that referenced his Asian heritage.

Perhaps remembering this episode, which saw Banks get pulled from a number of summer festival performances, she quickly deleted her tweets and instead continued to vent on Instagram.

Posting a text note from her phone, Banks raged: "Don't you ever in your pompous white life ever fix your stupid chapped face to say anything sideways about my religious beliefs and practices".

"This is you first warning," she concluded.

The rapper has now replaced the post with a message that reads "Stop apologising. No explanations."

Sia is yet to publicly respond.

Concerns over the 25-years-old's well-being have grown over recent months, as her public meltdowns become more frequent than her music.

She revealed herself as a practicing witch earlier this year during an interview with Broadly Vice: "My mother practised white table magic. Prayers to the ancestors and praying to saints and praying for all kind of protection."

She further explained on Twitter: "Black people are naturally born SEERS, DIVINERS, WITCHES AND WIZARDS. we have REAL supernatural powers, and the sooner we ALL learn to cultivate them and access them, the sooner we can REALLY fix s***".