PHOENIX -- Roughly a third of 300 potential jurors were dismissed Monday in the penalty retrial of convicted murderer Jodi Arias after telling a judge they had seen too much media coverage of her first trial to be impartial or had already made up their minds about her punishment.

Other jurors were let go due to work conflicts or language barriers, among other reasons, as jury selection began in the second attempt by prosecutors to secure a death sentence in the Arizona case that became a tabloid TV sensation.

Arias, 34, has acknowledged killing ex-boyfriend Travis Alexander in 2008 at his suburban Phoenix home but claimed it was self-defence. He suffered nearly 30 knife wounds, had his throat slit and was shot in the head.

Prosecutors argued it was premeditated murder carried out in a jealous rage when Alexander wanted to end their affair.

Arias, a former waitress, was found guilty last year, and the murder conviction will stand as lawyers spar again over whether she should die for the crime.

Arias was previously found unable to pay for her own attorneys and the cost to taxpayers for her defence so far has topped $2.5 million, Maricopa County spokeswoman Cari Gerchick said. The cost will keep rising during the penalty phase retrial, which is expected to last into December.

Another 100 prospective jurors were set to be brought in Wednesday. No proceeding were set Tuesday in the case.

Arias glanced back at the media at one point on Monday and smiled just before jurors started arriving. The victim's sister and her husband also sat in the courtroom watching the proceedings.

Some of the prospective jurors who were dismissed said they had already seen so much media coverage of the first trial that they couldn't put it out of their minds and would not be able to make a decision based only on information presented at the penalty retrial.

The upcoming proceedings will not be televised live after the judge ruled that no video footage can be broadcast until after the verdict.

If the new jury fails to reach a unanimous decision, the death penalty will be removed as an option and the judge will sentence Arias to spend her life behind bars or to be eligible for release after 25 years.

Arias' five-month trial began in January 2013 and was broadcast live, providing endless cable TV and tabloid fodder, including a recorded phone sex call between Arias and the victim, nude photos, bloody crime-scene pictures and a defendant who described her life story in intimate detail over 18 days on the witness stand.

Alexander's family sat in the front row of the courtroom throughout the trial, often sobbing, looking away from horrific photographs, and wincing as Arias described the victim as an abusive boyfriend who wanted nothing but sex.

It was a far cry from the man Alexander presented himself to be publicly -- a devout Mormon in search of his soul mate.

Trial watchers say the lack of live television coverage this time around will likely lead to less public interest in the case.

"It wasn't really until Jodi took the stand last time that it turned into a circus and built into a frenzy," said Phoenix criminal defence lawyer Dwane Cates.

Cates said the biggest problem prosecutors now face will be weeding out prospective jurors with an agenda, those "who want their 15 minutes of fame" and could potentially cause another mistrial.