American housewife Nancy Kissel, dubbed the "milkshake murderer", on Tuesday lost an appeal against her second conviction in Hong Kong for the 2003 murder of her banker husband.

The 49-year-old expatriate, serving a life sentence since 2005, was found guilty of drugging her husband -- a senior executive at US bank Merrill Lynch -- with a sedative-laced strawberry drink before clubbing him to death with a lead ornament in their luxury home.

She maintained she acted in self-defence against an abusive spouse, but she was convicted for a second time in 2011 following a retrial ordered by the city's top court.

Hong Kong's Court of Appeal judge Wally Yeung rejected Kissel's appeal on Tuesday, ruling out that the conviction was unsatisfactory.

"The evidence... is consistent with the deceased being attacked and killed when he was either unconscious or when his consciousness was impaired," Yeung said in his judgement.

Her defence team told the court during the appeal in October that Kissel suffered from depression and "had only killed the deceased in a frenzied attack provoked by threats and the deceased's physical assault on her".

The trial has gripped the former British colony, shining a spotlight on Hong Kong's elite expatriate community, and featuring sensational allegations of a heady mix of adultery, violence, spying, greed and enormous wealth.

The Michigan-born mother-of-three was first convicted of murder and handed a life sentence in 2005, but the Court of Final Appeal overturned the conviction in February 2010, citing legal errors, and ordered a fresh hearing. She was convicted again in 2011.

Kissel admitted to killing her husband and offered to plead guilty for manslaughter.

After killing her husband in their Tai Tam home, prosecutors accused Kissel of rolling up his body in a carpet and covering his head with plastic, leaving it in the bedroom for days before hiring workmen to carry it to a storeroom.

Prosecutors also argued that Kissel stood to gain up to $18 million from the death of her wealthy husband, saying she planned to run away with a TV repairman with whom she admitted having an affair in the US.