Lewis, 47, wrote in the Radio Times: "Progressive ideas should benefit everyone, but how can that be the case if we do not acknowledge female artists - the female artists who are symbols of empowerment to millions of young aspiring women?"
She added that as a result of the demise of male and female categories, "Women, predictably, have suffered as a result."
The Never Ever singer said: "It does not feel right and I have to ask why women now face being disregarded and excluded. Is it because we are not seen as equally bankable by the industry?
"How can this be ignored? How can they deny that experience of winning a Brit to another generation of girls?"
Lewis and her All Saints bandmates — Melanie Blatt and sisters Natalie and Nicole Appleton — were nominated for eight Brit awards and won two: Best British Single and Best British Video for Never Ever in 1998.
She said: "We won awards in categories that were gender-neutral, but in that moment we played a major part in ensuring that the Brits was a space for women to thrive. Is that still the case?"
A spokesperson for the Brit awards said in a statement: "We recognise this points to wider issues around the representation of women in music that must also be addressed.
"We are wholeheartedly committed to a considered review of the categories over the immediate months following this year's event, and this will include industry consultation and discussion, in line with what we instigated over the past five years, with any conclusions and actions made ahead of the 2024 event."
Female artists are nominated in other gender neutral categories including International Artist of the Year and Best New Act.
The Brits introduced gender neutral award categories in 2022.
When Adele picked up the Artist of the Year she said: "I understand why the name of this award has changed but I really love being a woman and being a female artist. I do. I’m really proud of us, I really, really am."
The 2023 Brit awards will take place at 8.30pm on Saturday, 11 February. They will be broadcast live on ITV1.
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