Amy Winehouse
A preview of Amy Winehouse's duet with Tony Bennett, her last ever recordings has been released. Reuters

Toxicology reports into the cause of the death of Amy Winehouse have shown there were "no illegal substances" in her body at the time of her death, reported the Guardian.

The singer's family said reports showed no drugs were present in her body at time of death, but alcohol was, though it is not yet known if it was a factor.

Previously Amy Winehouse's father believed her decision to stop drinking may have contributed to her death.

Mitch Winehouse told mourners at her funeral on 27 July that he thought his daughter tried to withdraw from drink too suddenly.

He said doctors had told Amy to gradually reduce her intake of alcohol and to avoid binging at all costs. The singer told him she couldn't do that.

"Toxicology results returned to the Winehouse family by authorities have confirmed that there were no illegal substances in Amy's system at the time of her death," the family said in a statement on Tuesday, reported the Guardian.

The singer's body was found on Saturday afternoon 23 July at her home in Camden, north London, with police saying her death at the age of 27 is "unexplained''.

The post mortem which took place at St Pancras Mortuary on July 25 proved inconclusive and the coroner's officer Sharon Duff described Winehouse's death as "non-suspicious" before adjourning it.

The Brit and Grammy award-winner had struggled with drink and drug addiction for many years and had recently spent time in rehab.

Other health problems the troubled singer reportedly suffered were traces of emphysema and eating disorders, notably bulimia, as exemplified by her dramatic weight loss.

The Brit soul singer gained notable praise with her second and last album, "Back to Black," which was released in 2006 and won five Grammy awards, reaching No. 1 in the UK two weeks after her demise.

Mitch Winehouse plans to launch a foundation in his daughter's name to help anyone suffering from drug related problems, and could include the induction of a rehabilitation centre.