A livid mum has accused her son's school teacher of racism after a video surfaced showing the educator singing an alternative version of the Happy Birthday song to her black son, referring to him as a monkey.

Mum Desarae Prather was incensed when she received a video of her 6-year-old son's classmates celebrating his birthday. Initially, the teacher can be heard singing the traditional version of Happy Birthday.

However, upon finishing, she asked the boy if he wanted "the funny version."

The woman is then heard singing: "Happy Birthday to you. You live in the zoo. You look like a monkey, and you smell like one too."

She concludes her song with laughter and instructs the other students to applaud, reports the Mirror US.

The incident took place at Floral Avenue Elementary School in Bartow, Florida.

Ms Desarae Prather told The Ledger: "I couldn't believe it."

She added: "It's nothing funny."

Prather stated that she had never heard this different version and immediately lodged a complaint with the school district. She also mentioned that her son is now too distressed to return to school.

She accused the teacher of being racist and said: "I don't approve of that, and that's you humiliating him in front of his peers."

She continued: "No child should have to go to school and feel like they can't confide in an authority figure without them calling them racial slurs, and that goes for any kid, not just my child. Now I have to seek counselling for him because he was crying for not to be back in her class or even go back to that school.

"I shouldn't have to wake up every day to see that my son feels this way."

Polk County Public School issued an online statement: "PCPS has been made aware of a video of a teacher singing to an elementary school student and his classmates.

"This is now being reviewed by district staff and our HR department. We understand and share the concerns about the teacher's actions and judgment.

"As a public school system we serve students and families of all cultures and backgrounds; we expect our employees to always keep that in mind as they interact with others."

The mother claims she hasn't yet received a call from the school district since her complaint and is now demanding the teacher be sacked.

She stated: "I feel like she should own up to her actions.

"I feel like she should write an apology to my son and my family, because it was unacceptable, and my son is going to be traumatised for life. This is going worldwide, and I feel as if she should get fired, because that's unacceptable."