Amy Winehouse was found dead in her home in Camden, north London, on July 23.
Story updated 1:15 p.m. ET: The local authority, Camden Council, said it was confident Reid "had made an error in good faith" when he appointed his wife, but said the matter was being investigated by Britain's Office for Judicial Complaints.
Story published 11:30 a.m. ET: The coroner who oversaw the inquest into the death of singer Amy Winehouse has resigned after her qualifications were questioned, officials in Britain said on Wednesday.
Suzanne Greenaway ruled in October that the 27-year-old soul singer had died from accidental alcohol poisoning.
However, she resigned after authorities learned she had not been a registered U.K. lawyer for five years as required. It means the verdict in Winehouse's case and 11 others carried out by Greenaway could be subject to a High Court challenge.
Winehouse's relatives said they were still absorbing the implications of the news.
Greenaway had been appointed an assistant deputy coroner in London by her husband, Coroner Andrew Reid. She had practiced law for a decade in her native Australia.
Reid said Wednesday he was "confident that all of the inquests handled were done so correctly" — but offered to hold inquests over again if the families of the deceased wanted it. Greenaway had been in the job since 2009.
Winehouse's family said it had not yet decided what to do.
In a statement, the family said it was "taking advice on the implications of this and will decide if any further discussion with the authorities is needed."
The Sun newspaper, which broke the story, said the dozens of verdicts given by Greenaway would only be overturned if they were challenged in Britain's High Court.
A security guard found Winehouse dead in bed on July 23 at her home in the Camden district of north London. The singer, known for her distinctive beehive hairdos and multiple Grammy-winning album "Back to Black," had battled drug and alcohol addiction for years.
The inquest heard evidence from a pathologist, Winehouse's doctor, the security guard who found her and a detective who described seeing three empty vodka bottles in her bedroom. It appears unlikely that a second inquest would produce a different conclusion about how she died.
The full statement issued by Reid on Wednesday was reported in north London newspaper, the Camden New Journal. It read: "I appointed my wife as an assistant deputy coroner as I believed at the time that her experience as a solicitor and barrister in Australia satisfied the requirements of the post. In November of last year it became apparent that I had made an error in the appointment process and I accepted her resignation.
"While I am confident that all of the inquests handled were done so correctly, I apologise if this matter causes distress to the families and friends of the deceased. I will be writing to the families affected to personally apologise and offer for their cases to reheard if requested."
Although the singer was adored by fans worldwide for her unique voice and style, praise for her singing was often eclipsed by lurid headlines about her destructive relationships and erratic behavior. Winehouse herself turned to her tumultuous life and personal demons for material, resulting in hit songs such as "Rehab" and "Love Is a Losing Game."
Msnbc.com's Alastair Jamieson in London and The Associated Press contributed to this report.