According to Home Office figures published in May, 43 per cent of black British males are on the NDNAD, while just 4.7 per cent of White males have been swabbed. Yet according to the offender's charity Nacro, "the lifetime offending rate for black males is in fact significantly lower than that for white males".
A spokeswoman for the EHRC said the Commission wrote to the National Police Improvement Agency, of which the NDNAD Unit is a part, in March, "asking for full details of their procedures, to see if they were lawful."
Having not received an adequate reply, the EHRC's legal committee will be discussing their options at their next meeting later this month.
"We will have to consider our legal options," said the spokeswoman. The Home Office advised the EHRC that it would conduct a Race Equality Impact Assessment on the police force's operational DNA guidance. But this has not satisfied the Commission.
The government has also commissioned a "citizen's inquiry" on the NDNAD, which the EHRC said it supported. But the legal committee will still consider what means it has under The Equality Act 2006 to force the police agency to deal with the apparently unequal constitution of the DNA database.
"It is a very serious concern that DNA samples from people from ethnic minority backgrounds are more likely to be on the DNA database than samples from white people," said the EHRC spokeswoman.
"Black people face the worrying prospect that they are three times more likely to be arrested than white people. This is not then reflected in the number of black people who go on to be charged or convicted," she added.
Asked why so many black British men had been captured on the database, Tony Lake, chairman of the NDNAD's governing board, said: "Because the DNA database is populated by people who are arrested for recordable offences no matter what their background".
The police are also criticised for storing the DNA details of people who are arrested or reported in connection with an offence but are subsequently discounted from investigations and have no recorded charges or convictions against them.
Lake refused to discuss how the disproportionate number of black men on the NDNAD might be addressed: "I'm not going to be drawn into that," he said.
Pressed further, he said: "Clearly there's an issue there and in order for people to make informed decisions there needs to be thorough research done about the geographies where these things happen - research into the route causes of the issue," Lake added.
Paul Davis, secretary of the Police Federation's operational policing sub-committee, was also skeptical of the statistics, though he had not analysed them. The Police Federation had not done its own research into the ethnicity of the NDNAD, he said. The Home Office figures might give only a limited view, he said.
Davis said there might be all sorts of explanations for the ethnic constituency of the National DNA Database. It might have something to do with 9/11, or it might only be in "particular areas" that the apparent disproportion was generated.
The Home Affairs Select Committee reported in June that young black males were more likely to be stopped, held and given more punitive sentences than young white males.
Yet, said Davis: "We can all show disproportion in different areas, but in fact the police service is working very hard to break down barriers. Unfortunately, there are still lots of organisations out there who want to keep kicking us when all most officers want to do is to go out and serve the community."
It is interesting to compare the issue of ethnicity and the NDNAD with the another controversy, that of the number of children on the system.
Davis was quick to ask if it was right that someone who committed a minor offence before the age of 16 had that record held against them for the rest of their life.
"We have an issue about criminalising the youth of our society, because they become our adults," said Davis, and Lake echoed his concern.
Terri Doughty, co-ordinator of Action of Rights for Children said the constitution of the NDNAD reflected a trend for children to be bound into the criminal justice system, which was "worrying" because research had shown that it led to their criminalisation.
The 10-year Edinburgh Study of Youth Transitions found that the most significant factor in determining whether children turned into criminals was whether they were picked up by the police when they were young, Doughty said. If they didn't, then they were more likely to grow out of their bad behaviour after their teens.
"If you hang about on an estate long enough you will catch a child doing something naughty. But because of the extension of the criminal justice system, naughtiness is being criminalised - it is now seen as a problem rather than something children do," said Doughty.
Both Doughty and Davis said performance targets where causing the police to record offences that they would not have felt the need to record before.
"What might have been before [reason] for an officer to use discretion is now a recordable offence that warrants DNA," said Davis. "Consequently, you are getting more and more people in the system.