A New Zealand Music Award winner and popular R&B singer has hit out at the ceremony and accused it of racism.

Aaradhna refused to accept her Tui award at tonight's star-studded ceremony after being placed in what she called a category for "brown" artists.

Aaradhna had already won the award for best female solo singer when she was announced as the winner of the best urban/hip-hop artist category.

But during her hard-hitting acceptance speech, she said she felt she couldn't be compared to the other finalists, rap crew SWIDT and PNC, because she was a singer.

"It feels like I've been placed in a category for brown people, that's what it feels like," the Porirua singer said.

Instead, she gave the Tui to SWIDT, a decision greeted by applause from the crowd.

"I believe you guys are the future of hip-hop," she said.

It is believed to be the first tine an artist has declined a Tui at the NZ Music Awards.

Aaradhna called for the awards to add a new category for soul or R&B singers.

The star later performed her song Brown Girl next to the words, "I'm more than the colour of my skin" splashed across the stage. She received a standing ovation.

It's not the first time Aaradhna has spoken out about racism.

In a letter posted to fans on Twitter in July, the 32-year-old says her song Brown Girl deals with the labels she was given "growing up as an Indian and Samoan New Zealander".

"I've seen and witnessed others including myself being automatically labelled for what we look like, what we wore, the way we spoke, where we resided," she wrote.

"I've been called a curry muncher, a dumb coconut, all kinds of names in the book while growing up and I've always felt like I was looked down on.