A US jury ordered far-right conspiracy theorist Alex Jones on Wednesday to pay nearly $1 billion in damages for falsely claiming that the deadly 2012 Sandy Hook elementary school shooting was a "hoax."

The jury in Connecticut, after three days of deliberations, awarded $965 million to the families of eight Sandy Hook victims and an FBI agent who brought the defamation case against Jones.

Jones, founder of the website InfoWars and host of a popular radio show, has been found liable in multiple defamation lawsuits brought by parents of the victims of the shooting in Newtown, Connecticut, which left 20 children and six teachers dead.

The 48-year-old Jones claimed for years on his show that the Sandy Hook shooting was "staged" by gun control activists and that the parents were "crisis actors," but has since acknowledged it was "100 per cent real."

A Texas jury ordered Jones last month to pay nearly $50 million in damages to Neil Heslin and Scarlett Lewis, whose six-year-old son Jesse was killed by the 20-year-old gunman behind the Sandy Hook shooting.

The latest damages trial was held in Waterbury, Connecticut, less than 20 miles (30 kilometres) from Newtown.

InfoWars declared bankruptcy in April and another company owned by Jones, Free Speech Systems, also recently filed for bankruptcy.