The prosecution is expected to open its case later against ex-News of the World journalists accused of phone hacking.
Jury selection began on Monday and is expected to be completed on Tuesday morning. The trial could last up to six months.
Rebekah Brooks and Andy Coulson, both former editors of Murdoch's now defunct News of the World tabloid, are accused of conspiring to illegally access voicemail messages on mobile phones belonging to politicians, the rich and famous, and victims of crime and ordinary people, to obtain exclusive news.
The two, who face trial with six others, deny all charges.
The scandal sent shockwaves through the British establishment and shook Murdoch's News Corp empire.
It revealed the close ties between press barons, police chiefs and senior politicians. The media industry is still at loggerheads with Cameron's government over how it should be regulated.
"This trial concerns allegations of criminal conduct at the News of the World and the Sun newspapers which preceded the closure of the News of the World," the judge, Justice John Saunders, said as jury selection began for the trial.
"It's an important case. The trial we are about to start will take a considerable length of time. It's estimated the case may last until Easter."
Detectives launched an investigation in January 2011 and since then more than 125 people have been arrested and more than 40 charged.
The most prominent are Coulson, 45, and Brooks, a close friend of Cameron. He attended her wedding in 2009 along with the then-Prime Minister Gordon Brown.
Brooks, 45, was the first female editor of Murdoch's top-selling Sun paper and had risen to become head of News International, News Corp's British newspaper arm, when the furor over phone-hacking led to her resignation.
