The family of Amy Winehouse is "taking advice" over revelations that the inquest into her death could be declared invalid.

It comes after coroner Suzanne Greenaway, who oversaw proceedings, resigned because she was not qualified to practise in Britain.

Ms Greenaway had been appointed to her post by Andrew Reid, the coroner for inner north London, who is also her husband. The Office for Judicial Complaints has now launched an investigation into Dr Reid's conduct.

In a statement, the late singer's relatives said: "The Winehouse family is taking advice on the implications of this and will decide if any further discussion with the authorities is needed."

Ms Greenaway took on the role of assistant deputy coroner in July 2009 but stepped down in November when it emerged she did not have the requisite five years' experience in the Law Society.

In October, she had recorded a verdict of misadventure after the Rehab star, 27, died of alcohol poisoning in her Camden flat in north London.

Dr Reid said he appointed his wife - who worked as a solicitor and barrister in Australia - in the belief that her previous experience "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," he added.

"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."

A spokesman for the Office for Judicial Complaints said it had "been made aware of the concerns" and had launched a conduct investigation.