Lawyers for Robert William Pickton — convicted in 2007 of killing six women who disappeared from Vancouver's Downtown Eastside — will appear before the B.C. Court of Appeal on Monday in an attempt to get a new trial.

Pickton was found guilty of six counts of second-degree murder in December 2007 in the deaths of Sereena Abotsway, Mona Wilson, Andrea Joesbury, Georgina Papin, Marnie Frey and Brenda Wolfe. He was sentenced two days later to a term of life imprisonment with no chance of parole for 25 years.

Pickton, 59, initially faced 26 first-degree murder counts, but the trial judge separated the charges into two trials to simplify the process.

His saga continues Monday, when the B.C. Court of Appeal will begin hearing duelling appeals by both the Crown and the defence.

The Crown would like Pickton convicted of first-degree murder, while the defence wants a retrial on second-degree murder charges.

One of the Crown's appeal arguments will be that the trial judge erred in deciding to hear only six counts in the initial trial.

The Crown will also argue that the judge erred by failing to instruct the jury that dismemberment and disposal of the victims' remains on the Pickton property in Port Coquitlam, B.C., was relevant to the issue of planning and deliberation, a component of a first-degree murder charge.

Crown prosecutors want to ensure that if Pickton is granted a new trial, he will face all 26 charges — all for first-degree murder.

"Crown's position is that if Mr. Pickton's six convictions are upheld and all his avenues of appeal are exhausted, then it's not the Crown's intention to proceed with the additional 20 counts," Crown spokesperson Neil Mackenzie said.

"However, if there is to be a new trial, then it may be a new trial on all 26 counts. But that's just one of the possible outcomes of the appeal process."

Pickton's new lawyer, Gil McKinnon, will argue that B.C. Supreme Court Justice James Williams made several errors during the trial. McKinnon, who specializes in appeals, will replace high-profile lawyer Peter Ritchie.

The defence appeal will focus on the judge's charge to the jury and how he dealt with one of the juror's questions.

Ultimately, Williams ended up changing his instruction to the jury, saying he had been "not sufficiently precise" and "in error" in three paragraphs of his original charge.

He told jurors they could consider whether they believed Pickton actually shot some of the victims, or whether he was an active participant but didn't pull the trigger.

Pickton will not be in the courtroom during the hearing. He will remain at the North Fraser Pretrial Centre in Port Coquitlam.

The court has set aside nine days for Pickton's appeal. Lawyers say there likely won't be a decision for several months.

With files from the Canadian Press