Black and Asian women earn a weekly average of £187
A TUC report says on average, black and Asian men are paid £97 a week less than their white colleagues.
Pakistani and Bangladeshi men earn £150 per week less than white men, while the difference is £115 for Caribbean men and £116 for Africans.
It also shows black and Asian women earn £7 per week more than white women - but the TUC says this is because they are more likely to work full-time.
The director of the Low Pay Unit, Richard Towers, told BBC News that within the same job, people tend to be paid the same.
The problem is that many ethnic minorities live in deprived areas and have to take jobs in low-paid industries such as textiles.
Factors such as educational qualifications, language and dependence on public transport also have an effect.
Changes in law
But the TUC says direct discrimination plays a part in the pay discrepancies in some workplaces.
It wants race relations laws to be extended from the public to the private sector.
It is calling for trade unions and the Commission for Racial Equality to be given the right to take collective cases on behalf of individuals or groups of members.
The TUC says the government should also encourage employers to regularly monitor pay data to ensure equality.
The CRE itself was more cautious on the need for a change in the law.
Deputy chair Beverley Bernard told BBC Radio 4's Today programme the figures were "startling" but "mixed", and she would like to find out more before addressing the question of legislation.
In the meantime, she said, disgruntled workers had two options to tackle pay discrimination.
"Workers could join together under the same organisation to challenge this under the employment tribunal.
"Two, if there is sufficient evidence that discrimination is consistently going on in any organisation, the CRE is obliged to look at formal investigations."
'Unfairness'
The study, Black and Underpaid, is launched to coincide with the TUC's Black Workers' Conference, which opens in Southport on Friday.
TUC General Secretary John Monks said: "New laws in the public sector... must now be extended to end the unfairness in pay for black and Asian workers.
"These workers already suffer twice the levels of unemployment, lack of promotion opportunities and racial harassment.
"Unions are seeking to work in partnership with employers and the government to end this disadvantage."