A Florida jury has ordered RJ Reynolds tobacco to pay $US23.6 billion ($A25.53 billion) to the wife of a longtime smoker who died of lung cancer in a verdict seen as one of the largest for a single plaintiff in state history.

In addition to the punitive damages, Friday’s verdict also awarded more than $US16 million in compensatory damages to the estate of Michael Johnson Sr.

During the four-week trial, lawyers for Johnson’s widow Cynthia Robinson argued that the RJ Reynolds Tobacco Company was negligent in informing consumers of the dangers of consuming tobacco and thus led to Johnson contracting lung cancer from smoking cigarettes.

They said Johnson had become “addicted” to cigarettes and failed multiple attempts to quit smoking.

The Escambia County jury returned its verdict after some 15 hours of deliberations.

“RJ Reynolds took a calculated risk by manufacturing cigarettes and selling them to consumers without properly informing them of the hazards,” Robinson’s lawyer Willie Gary said in a statement.

“As a result of their negligence, my client’s husband suffered from lung cancer and eventually lost his life.

“We hope that this verdict will send a message to RJ Reynolds and other big tobacco companies that will force them to stop putting the lives of innocent people in jeopardy.”

RJ Reynolds plans to appeal the court decision and verdict, vice president and assistant general counsel J Jeffery Raborn said.

The landmark award was “far beyond the realm of reasonableness and fairness”, he charged in a statement.

Reynolds is “confident that the court will follow the law and not allow this runaway verdict to stand”, Raborn added, calling the damages “grossly excessive and impermissible under state and constitutional law”.

Smoking remains the leading preventable cause of premature death in the US, killing nearly half a million Americans each year, health experts say.

Some 18 per cent of Americans now smoke, down from 42 per cent in the 1960s.

The RJ Reynolds court verdict comes only days after its parent company, Reynolds American, announced it would acquire rival Lorillard to create a behemoth aimed at conquering the growing e-cigarette market.

Recent growth in e-cigarettes, which deliver nicotine in a vapour rather than smoke, comes as conventional cigarette sales drop amid tight consumer spending and health concerns.