Labour has pledged to extend full equal pay rights to ethnic minority workers and disabled people if it wins power.
Currently women have stronger protections on pay than other groups.
Under the party’s plans a new Race Equality Act would enshrine in law the full right to equal pay for black, Asian and ethnic minority people, as well as disabled people.
But Minister for Equalities Kemi Badenoch said this would “be a bonanza for dodgy, activist lawyers”.
She said the proposed legislation would “set people against each other and see millions wasted on pointless red tape”.
“It is obviously already illegal to pay someone less because of their race,” she added.
Labour said any changes they would make if they won the next general election would be phased in to give employers time to adjust.
Its proposals would also address “dual discrimination”, allowing employees to bring a single claim if they feel they have been subject to, for example, both sexism and racism.
The principle that women and men are entitled to equal pay for equal work is set out in the 2010 Equality Act.
The act applies across Great Britain but Northern Ireland has its own equality legislation.
Pay inequalities on other grounds can still be challenged through a claim of direct discrimination.
However, Labour said its plans, which would be subject to consultation, would mean equal pay claims on the basis of ethnicity or disability would be treated the same as those made by women
The party has already said a Labour government would require large employers to publish ethnicity and disability pay gap reports to reveal any disparities in wages between different groups.
Companies with more than 250 employees in England, Wales and Scotland have been required to publish their gender pay gap statistics since 2017 but this is not mandatory for ethnicity or disability.
BBC