Chief constables across England and Wales have been told to ignore a landmark ruling by the European court of human rights and carry on adding the DNA profiles of tens of thousands of innocent people to a national DNA database.

Senior police officers have also been "strongly advised" that it is "vitally important" that they resist individual requests based on the Strasbourg ruling to remove DNA profiles from the national database in cases such as wrongful arrest, mistaken identity, or where no crime has been committed.

European human rights judges ruled last December in the S and Marper case that the blanket and indiscriminate retention of the DNA profiles and fingerprints of 850,000 people arrested but never convicted of any offence amounts to an unlawful breach of their rights.

Britain already has the largest police national DNA database in the world, with 5.8m profiles, including one in three of all young black males. Thousands more are being added each week.

So far the Home Office has responded to the judgment by proposing a controversial package to keep DNA profiles of the innocent for six to 12 years, depending on the seriousness of the offence. The official consultation period ended today.

The advice to senior officers comes in a letter from the Association of Chief Police Officers criminal records office. The letter, seen by the Guardian, tells chief constables that new Home Office guidelines following the ruling in the case of S and Marper are not expected to take effect until 2010.

"Until that time, the current retention policy on fingerprints and DNA remains unchanged," it says. "Individuals who consider they fall within the ruling in the S and Marper case should await the full response to the ruling by the government prior to seeking advice and/or action from the police service in order to address their personal issue on the matter.

"Acpo strongly advise that decisions to remove records should not be based on [the government's] proposed changes. It is therefore vitally important that any applications for removals of records should be considered against current legislation."

Chris Huhne, the Liberal Democrats' shadow home secretary, said it was clear from the letter that the government intends to string out its response to the European court ruling that they should not keep the DNA of innocent people.

"It is unacceptable that new guidance won't be provided to police until 2010. In that time thousands more innocent people will have been added to the database, where they will remain for years.

"It is not up to police forces to ignore court judgments because they or their masters do not like them."

The tone of the letter is in sharp contrast to what the Home Office told the House of Lords in June when peers sharply criticised the government's intention to push through their plan to keep innocent people's DNA for up to 12 years by using "back door" secondary legislation to get it through parliament. The Home Office told peers that they could not afford the delay that would be involved in making the changes in primary legislation that would allow MPs and peers to fully debate the changes.

Home Office officials said they face a possible "surge of pressure" from individuals seeking deletion of their data from the relevant databases. Ministers have already received some legal challenges.

But the Lords committee on delegated powers and regulatory reform has told ministers that provision "about this important and complex subject should be in primary legislation".